Protease-deficient mutants of trichoderma for producing polypeptides

ABSTRACT

The present invention relates to mutants of a parent  Trichoderma  strain, comprising a polynucleotide encoding a polypeptide and one or more (several) genes selected from the group consisting of a first subtilisin-like serine protease gene, a first aspartic protease gene, a trypsin-like serine protease gene, a second subtilisin-like serine protease gene, and a second aspartic protease gene, wherein the one or more (several) genes are modified rendering the mutant strain deficient in the production of one or more (several) enzymes selected from the group consisting of a first subtilisin-like serine protease, a first aspartic protease, a trypsin-like serine protease, a second subtilisin-like serine protease, and a second aspartic protease, respectively, compared to the parent  Trichoderma  strain when cultivated under identical conditions. The present invention also relates to methods of producing a polypeptide in such mutants and methods for producing such mutants.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of U.S. application Ser. No. 13/516,433 filed on Jun. 15, 2012, now U.S. Pat. No. 8,986,974, which is a 35 U.S.C. 371 national application of PCT/US2010/061105 filed on Dec. 17, 2010 and claims priority from U.S. Provisional Application Ser. No. 61/287,844 filed on Dec. 18, 2009, which applications are fully incorporated herein by reference.

REFERENCE TO A SEQUENCE LISTING

This application contains a Sequence Listing in computer readable form, which is incorporated herein by reference.

BACKGROUND OF THE INVENTION

Field of the Invention

The present invention relates to methods of producing polypeptides in protease-deficient Trichoderma mutant strains, the protease-deficient Trichoderma mutant strains, and methods of obtaining the protease-deficient Trichoderma mutant strains.

Description of the Related Art

Trichoderma has been shown to be useful as a host cell for the recombinant production of polypeptides having biological activity (WO 96/00787, WO 97/26330). Trichoderma hosts with the desirable traits of increased protein expression and secretion may not necessarily have the most desirable characteristics for successful fermentation. The fermentation may not be optimal because of the production of biological substances, e.g., enzymes, detrimental to the production, recovery, or application of a particular polypeptide of interest.

Martinez et al., 2008, Nature Biotechnology 26:553-560, describe the genome sequencing and analysis of the biomass-degrading fungus Trichoderma reesei. Dienes et al., 2007, Enzyme and Microbial Technology 40: 1087-1094, disclose the identification of a trypsin-like serine protease from Trichoderma reesei QM9414. Eneyskaya et al., 1999, Appl. Microbiol. Biotechnol. 52: 226-231, describe an acid protease from Trichoderma reesei. Haub et al., 1990, J. Biotechnology 16: 187-198, disclose the formation of extracellular proteases from Trichoderma reesei QM9414. Hagspiel et al., 1989, Appl. Microbiol. Biotechnol. 32: 61-67, disclose protease activity and proteolytic modification of cellulases from a Trichoderma reesei QM9414 selectant. WO 2006/073839 discloses fungal acidic proteases.

WO 2007/045248 describes use of fungal mutants for expression of heterologous polypeptides.

The present invention relates to improved Trichoderma hosts that combine the capacity for expression of commercial quantities of a polypeptide of interest while being deficient in the production of protease(s) that can complicate recovery and downstream processing of the polypeptide.

SUMMARY OF THE INVENTION

The present invention relates to mutants of a parent Trichoderma strain, comprising a polynucleotide encoding a polypeptide and one or more (several) genes selected from the group consisting of a first subtilisin-like serine protease gene, a first aspartic protease gene, a trypsin-like serine protease gene, a second subtilisin-like serine protease gene, and a second aspartic protease gene, wherein the one or more (several) genes are modified rendering the mutant strain deficient in the production of one or more (several) enzymes selected from the group consisting of a first subtilisin-like serine protease, a first aspartic protease, a trypsin-like serine protease, a second subtilisin-like serine protease, and a second aspartic protease, respectively, compared to the parent Trichoderma strain when cultivated under identical conditions.

The present invention also relates to methods of producing a polypeptide, comprising:

(a) cultivating a mutant of a parent Trichoderma strain in a medium for the production of the polypeptide, wherein the mutant strain comprises a polynucleotide encoding the polypeptide and one or more (several) genes selected from the group consisting of a first subtilisin-like serine protease gene, a first aspartic protease gene, a trypsin-like serine protease gene, a second subtilisin-like serine protease gene, and a second aspartic protease gene, wherein the one or more (several) genes are modified rendering the mutant strain deficient in the production of one or more (several) enzymes selected from the group consisting of a first subtilisin-like serine protease, a first aspartic protease, a trypsin-like serine protease, a second subtilisin-like serine protease, and a second aspartic protease, respectively, compared to the parent Trichoderma strain when cultivated under identical conditions; and

(b) recovering the polypeptide from the cultivation medium.

The present invention further relates to methods of obtaining mutants of a parent Trichoderma strain, comprising:

(a) modifying one or more (several) genes selected from the group consisting of a first subtilisin-like serine protease gene, a first aspartic protease gene, a trypsin-like serine protease gene, a second subtilisin-like serine protease gene, and a second aspartic protease gene; and

(b) identifying a mutant strain from step (a) wherein the one or more (several) genes selected from the group consisting of a first subtilisin-like serine protease gene, a first aspartic protease gene, a trypsin-like serine protease gene, a second subtilisin-like serine protease gene, and a second aspartic protease gene are modified rendering the mutant strain deficient in the production of one or more (several) enzymes selected from the group consisting of a first subtilisin-like serine protease, a first aspartic protease, a trypsin-like serine protease, a second subtilisin-like serine protease, and a second aspartic protease, respectively, compared to the parent Trichoderma strain when cultivated under identical conditions.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 shows a restriction map of pDM156.2.

FIG. 2 shows a restriction map of pEmY21.

FIG. 3 shows a restriction map of pEmY23.

FIG. 4 shows a restriction map of pWTY1470-19-07.

FIG. 5 shows a restriction map of pWTY1515-2-01.

FIG. 6 shows a restriction map of pJaL504-[Bam HI].

FIG. 7 shows a restriction map of pJaL504-[Bgl II].

FIG. 8 shows a restriction map of pJaL574.

FIG. 9 shows a restriction map of pWTY1449-02-01.

FIG. 10 shows a restriction map of pJfyS1540-75-5.

FIG. 11 shows a restriction map of pJfyS1579-1-13.

FIG. 12 shows a restriction map of pJfyS1579-8-6.

FIG. 13 shows a restriction map of pJfyS1579-21-16.

FIG. 14 shows a restriction map of pAlLo1492-24.

FIG. 15 shows a restriction map of pJfyS1579-35-2.

FIG. 16 shows a restriction map of pJfyS1579-41-11.

FIG. 17 shows a restriction map of pDAtw18.

FIG. 18 shows a restriction map of pSaMe-AaXYL.

FIG. 19 shows a restriction map of pAgJg111.

FIG. 20 shows a restriction map of pAgJg116.

FIG. 21 shows a restriction map of pAgJg115.

FIG. 22 shows a restriction map of pAgJg117.

FIG. 23 shows a restriction map of pAgJg118.

FIG. 24 shows residual cellulase activity at 40° C. for two weeks of the broths from Trichoderma reesei AgJg117-3-10A (double protease deletion mutant) and Trichoderma reesei AgJg118-02-2E (triple protease deletion mutant) compared to the broth of the parent strain Trichoderma reesei strain 981-O-8 under the same conditions.

FIG. 25 shows a restriction map of pJfyS152.

FIG. 26 shows a restriction map of pJfyS153.

DEFINITIONS

Subtilisin-like serine protease: The term “subtilisin-like serine protease” means a protease with a substrate specificity similar to subtilisin that uses a serine residue for catalyzing the hydrolysis of peptide bonds in peptides and proteins. Subtilisin-like proteases (subtilases) are serine proteases characterized by a catalytic triad of the three amino acids aspartate, histidine, and serine. The arrangement of these catalytic residues is shared with the prototypical subtilisin from Bacillus licheniformis (Siezen and Leunissen, 1997, Protein Science 6: 501-523). For purposes of the present invention, subtilisin-like serine protease activity is determined according to the procedure described in Example 13.

Aspartic protease: The term “aspartic protease” means a protease that uses an aspartate residue(s) for catalyzing the hydrolysis of peptide bonds in peptides and proteins. Aspartic proteases are a family of protease enzymes that use an aspartate residue for catalysis of their peptide substrates. In general, they have two highly-conserved aspartates in the active site and are optimally active at acidic pH (Szecsi, 1992, Scand. J. Clin. Lab. In vest. Suppl. 210: 5-22). For purposes of the present invention, aspartic protease activity is determined according to the procedure described by Aikawa et al., 2001, J. Biochem. 129: 791-794.

Trypsin-like serine protease: The term “trypsin-like serine protease” means a protease with a substrate specificity similar to trypsin that uses a serine residue for catalyzing the hydrolysis of peptide bonds in peptides and proteins. For purposes of the present invention, trypsin-like serine protease activity is determined according to the procedure described by Dienes et al., 2007, supra, or Example 20.

Deficient: The term “deficient” means a Trichoderma mutant strain that produces no detectable activity of one or more (several) enzymes selected from the group consisting of a first subtilisin-like serine protease, a first aspartic protease, a trypsin-like serine protease, and a second aspartic protease compared to the parent Trichoderma strain when cultivated under identical conditions, or, in the alternative, produces preferably at least 25% less, more preferably at least 50% less, even more preferably at least 75% less, and most preferably at least 95% less of one or more (several) enzymes selected from the group consisting of a first subtilisin-like serine protease, a first aspartic protease, a trypsin-like serine protease, a second subtilisin-like serine protease, and a second aspartic protease than the parent Trichoderma strain when cultivated under identical conditions. The level of protease produced by a Trichoderma mutant strain of the present invention may be determined using methods described herein or known in the art.

Isolated or Purified: The term “isolated” or “purified” means a polypeptide or polynucleotide that is removed from at least one component with which it is naturally associated. For example, a polypeptide may be at least 1% pure, e.g., at least 5% pure, at least 10% pure, at least 20% pure, at least 40% pure, at least 60% pure, at least 80% pure, at least 90% pure, or at least 95% pure, as determined by SDS-PAGE, and a polynucleotide may be at least 1% pure, e.g., at least 5% pure, at least 10% pure, at least 20% pure, at least 40% pure, at least 60% pure, at least 80% pure, at least 90% pure, or at least 95% pure, as determined by agarose electrophoresis.

Mature polypeptide: The term “mature polypeptide” means a polypeptide in its final form following translation and any post-translational modifications, such as N-terminal processing, C-terminal truncation, glycosylation, phosphorylation, etc. In one aspect, the mature polypeptide is amino acids 20 to 882 of SEQ ID NO: 2 based on the SignalP program (Nielsen et al., 1997, Protein Engineering 10: 1-6) that predicts amino acids 1 to 19 of SEQ ID NO: 2 are a signal peptide. In another aspect, the mature polypeptide is amino acids 21 to 407 of SEQ ID NO: 4 based on the SignalP program that predicts amino acids 1 to 20 of SEQ ID NO: 4 are a signal peptide. In another aspect, the mature polypeptide is amino acids 20 to 259 of SEQ ID NO: 6 based on the SignalP program that predicts amino acids 1 to 19 of SEQ ID NO: 6 are a signal peptide. In another aspect, the mature polypeptide is amino acids 16 to 540 of SEQ ID NO: 100 based on the SignalP program that predicts amino acids 1 to 15 of SEQ ID NO: 100 are a signal peptide. [In another aspect, the mature polypeptide is amino acids 18 to 395 of SEQ ID NO: 108 based on the SignalP program that predicts amino acids 1 to 17 of SEQ ID NO: 108 are a signal peptide.

Mature polypeptide coding sequence: The term “mature polypeptide coding sequence” means a polynucleotide that encodes a mature polypeptide having enzyme activity. In one aspect, the mature polypeptide coding sequence is nucleotides 58 to 2774 of SEQ ID NO: 1 based on the SignalP program (Nielsen et al., 1997, supra) that predicts nucleotides 1 to 57 of SEQ ID NO: 3 encode a signal peptide. In another aspect, the mature polypeptide coding sequence is nucleotides 61 to 1299 of SEQ ID NO: 3 based on the SignalP program that predicts nucleotides 1 to 60 of SEQ ID NO: 1 encode a signal peptide. In another aspect, the mature polypeptide coding sequence is nucleotides 58 to 930 of SEQ ID NO: 5 based on the SignalP program that predicts nucleotides 1 to 57 of SEQ ID NO: 5 encode a signal peptide. In another aspect, the mature polypeptide coding sequence is nucleotides 46 to 1681 of SEQ ID NO: 99 based on the SignalP program that predicts nucleotides 1 to 45 of SEQ ID NO: 99 encode a signal peptide. In another aspect, the mature polypeptide coding sequence is nucleotides 52 to 1339 of SEQ ID NO: 107 based on the SignalP program that predicts nucleotides 1 to 51 of SEQ ID NO: 107 encode a signal peptide.

Identity: The relatedness between two amino acid sequences or between two nucleotide sequences is described by the parameter “identity”.

For purposes of the present invention, the degree of identity between two amino acid sequences is determined using the Needleman-Wunsch algorithm (Needleman and Wunsch, 1970, J. Mol. Biol. 48: 443-453) as implemented in the Needle program of the EMBOSS package (EMBOSS: The European Molecular Biology Open Software Suite, Rice et al., 2000, Trends in Genetics 16: 276-277), preferably version 3.0.0 or later. The optional parameters used are gap open penalty of 10, gap extension penalty of 0.5, and the EBLOSUM62 (EMBOSS version of BLOSUM62) substitution matrix. The output of Needle labeled “longest identity” (obtained using the -nobrief option) is used as the percent identity and is calculated as follows: (Identical Residues×100)/(Length of Alignment−Total Number of Gaps in Alignment)

For purposes of the present invention, the degree of identity between two deoxyribonucleotide sequences is determined using the Needleman-Wunsch algorithm (Needleman and Wunsch, 1970, supra) as implemented in the Needle program of the EMBOSS package (EMBOSS: The European Molecular Biology Open Software Suite, Rice et al., 2000, supra), preferably version 3.0.0 or later. The optional parameters used are gap open penalty of 10, gap extension penalty of 0.5, and the EDNAFULL (EMBOSS version of NCBI NUC4.4) substitution matrix. The output of Needle labeled “longest identity” (obtained using the -nobrief option) is used as the percent identity and is calculated as follows: (Identical Deoxyribonucleotides×100)/(Length of Alignment−Total Number of Gaps in Alignment)

Polypeptide fragment: The term “polypeptide fragment” means a polypeptide having one or more (several) amino acids deleted from the amino and/or carboxyl terminus of a mature polypeptide, wherein the fragment has enzyme activity, e.g., subtilisin-like serine protease, aspartic protease, or serine protease activity. In one aspect, a fragment contains at least 740 amino acid residues, e.g., at least 780 amino acid residues or at least 820 amino acid residues of the mature polypeptide of SEQ ID NO: 2 or a homologous sequence thereof. In another aspect, a fragment contains at least 320 amino acid residues, e.g., at least 340 amino acid residues or at least 360 amino acid residues of the mature polypeptide of SEQ ID NO: 4 or a homologous sequence thereof. In another aspect, a fragment contains at least 210 amino acid residues, e.g., at least 220 amino acid residues or at least 230 amino acid residues of the mature polypeptide of SEQ ID NO: 6 or a homologous sequence thereof. In another aspect, a fragment contains at least 460 amino acid residues, e.g., at least 480 amino acid residues or at least 500 amino acid residues of the mature polypeptide of SEQ ID NO: 100 or a homologous sequence thereof. In another aspect, a fragment contains at least 320 amino acid residues, e.g., at least 340 amino acid residues or at least 360 amino acid residues of the mature polypeptide of SEQ ID NO: 108 or a homologous sequence thereof.

Subsequence: The term “subsequence” means a nucleotide sequence having one or more (several) nucleotides deleted from the 5′ and/or 3′ end of a mature polypeptide coding sequence, wherein the subsequence encodes a polypeptide fragment having enzyme activity, e.g., subtilisin-like serine protease, aspartic protease, or serine protease. In one aspect, a subsequence contains at least 2220 nucleotides, e.g., at least 2340 nucleotides or at least 2460 nucleotides of the mature polypeptide coding sequence of SEQ ID NO: 1 or the cDNA sequence thereof, or a homologous sequence thereof. In another aspect, a subsequence contains at least 960 nucleotides, e.g., at least 1020 nucleotides or at least 1080 nucleotides of the mature polypeptide coding sequence of SEQ ID NO: 3 or the cDNA sequence thereof, or a homologous sequence thereof. In another aspect, a subsequence contains at least 630 nucleotides, e.g., at least 660 nucleotides or at least 690 nucleotides of the mature polypeptide coding sequence of SEQ ID NO: 5 or the cDNA sequence thereof, or a homologous sequence thereof. In another aspect, a subsequence contains at least 1380 nucleotides, e.g., at least 1440 nucleotides or at least 1500 nucleotides of the mature polypeptide coding sequence of SEQ ID NO: 99 or the cDNA sequence thereof, or a homologous sequence thereof. In another aspect, a subsequence contains at least 960 nucleotides, e.g., at least 1020 nucleotides, or at least 1080 nucleotides of the mature polypeptide coding sequence of SEQ ID NO: 107 or the cDNA sequence thereof, or a homologous sequence thereof.

Allelic variant: The term “allelic variant” means any of two or more alternative forms of a gene occupying the same chromosomal locus. Allelic variation arises naturally through mutation, and may result in polymorphism within populations. Gene mutations can be silent (no change in the encoded polypeptide) or may encode polypeptides having altered amino acid sequences. An allelic variant of a polypeptide is a polypeptide encoded by an allelic variant of a gene.

Coding sequence: The term “coding sequence” means a polynucleotide, which directly specifies the amino acid sequence of a polypeptide. The boundaries of the coding sequence are generally determined by an open reading frame, which usually begins with the ATG start codon or alternative start codons such as GTG and TTG and ends with a stop codon such as TAA, TAG, and TGA. The coding sequence may be a genomic DNA, cDNA, synthetic DNA, or a combination thereof.

cDNA: The term “cDNA” means a DNA molecule that can be prepared by reverse transcription from a mature, spliced, mRNA molecule obtained from a eukaryotic cell. cDNA lacks intron sequences that may be present in the corresponding genomic DNA. The initial, primary RNA transcript is a precursor to mRNA that is processed through a series of steps, including splicing, before appearing as mature spliced mRNA.

Nucleic acid construct: The term “nucleic acid construct” means a nucleic acid molecule, either single- or double-stranded, which is isolated from a naturally occurring gene or is modified to contain segments of nucleic acids in a manner that would not otherwise exist in nature or which is synthetic. The term nucleic acid construct is synonymous with the term “expression cassette” when the nucleic acid construct contains the control sequences required for expression of a coding sequence.

Control sequences: The term “control sequences” means all components necessary for the expression of a polynucleotide encoding a polypeptide. Each control sequence may be native or foreign to the polynucleotide encoding the polypeptide or native or foreign to each other. Such control sequences include, but are not limited to, a leader, polyadenylation sequence, propeptide sequence, promoter, signal peptide sequence, and transcription terminator. At a minimum, the control sequences include a promoter, and transcriptional and translational stop signals. The control sequences may be provided with linkers for the purpose of introducing specific restriction sites facilitating ligation of the control sequences with the coding region of the polynucleotide encoding a polypeptide.

Operably linked: The term “operably linked” means a configuration in which a control sequence is placed at an appropriate position relative to the coding sequence of a polynucleotide such that the control sequence directs the expression of the coding sequence.

Expression: The term “expression” includes any step involved in the production of a polypeptide including, but not limited to, transcription, post-transcriptional modification, translation, post-translational modification, and secretion.

Expression vector: The term “expression vector” means a linear or circular DNA molecule that comprises a polynucleotide encoding a polypeptide and is operably linked to additional nucleotides that provide for its expression.

Host cell: The term “host cell” means any cell type that is susceptible to transformation, transfection, transduction, and the like with a nucleic acid construct or expression vector comprising a polynucleotide. The term “host cell” encompasses any progeny of a parent cell that is not identical to the parent cell due to mutations that occur during replication.

Modification: The term “modification” means introduction, substitution, or removal of one or more (several) nucleotides in a gene or a control sequence required for the transcription or translation thereof, or gene disruption, gene conversion, gene deletion, or random or specific mutagenesis of a gene, e.g., a first subtilisin-like serine protease gene, a first aspartic protease gene, a trypsin-like serine protease gene, a second subtilisin-like serine protease gene, a second aspartic protease gene, or a combination thereof. The deletion of one or more (several) of the first subtilisin-like serine protease gene, the first aspartic protease gene, the trypsin-like serine protease gene, the second subtilisin-like serine protease gene, and/or the second aspartic protease gene may be partial or complete. The modification results in a decrease in or elimination (inactivation) of expression of the first subtilisin-like serine protease, the first aspartic protease, the trypsin-like serine protease, the second subtilisin-like serine protease, the second aspartic protease, or a combination thereof. In a preferred aspect, one or more (several) of the first subtilisin-like serine protease gene, the first aspartic protease gene, the trypsin-like serine protease gene, the second subtilisin-like serine protease gene, and the second aspartic protease gene are inactivated.

DETAILED DESCRIPTION OF THE INVENTION

The present invention relates to mutants of a parent Trichoderma strain, comprising a polynucleotide encoding a polypeptide and one or more (several) genes selected from the group consisting of a first subtilisin-like serine protease gene, a first aspartic protease gene, a trypsin-like serine protease gene, a second subtilisin-like serine protease gene, and a second aspartic protease gene, wherein the one or more (several) genes are modified rendering the mutant strain deficient in the production of one or more (several) enzymes selected from the group consisting of a first subtilisin-like serine protease, a first aspartic protease, a trypsin-like serine protease, a second subtilisin-like serine protease, and a second aspartic protease, respectively, compared to the parent Trichoderma strain when cultivated under identical conditions.

The present invention also relates to methods of producing a polypeptide, comprising: (a) cultivating a mutant of a parent Trichoderma strain in a medium for the production of the polypeptide, wherein the mutant strain comprises a polynucleotide encoding the polypeptide and one or more (several) genes selected from the group consisting of a first subtilisin-like serine protease gene, a first aspartic protease gene, a trypsin-like serine protease gene, a second subtilisin-like serine protease gene, and a second aspartic protease gene, wherein the one or more (several) genes are modified rendering the mutant strain deficient in the production of one or more (several) enzymes selected from the group consisting of a first subtilisin-like serine protease, a first aspartic protease, a trypsin-like serine protease, a second subtilisin-like serine protease, and a second aspartic protease, respectively, compared to the parent Trichoderma strain when cultivated under identical conditions; and (b) recovering the polypeptide from the cultivation medium.

The present invention further relates to methods of obtaining mutants of a parent Trichoderma strain, comprising: (a) modifying one or more (several) genes selected from the group consisting of a first subtilisin-like serine protease gene, a first aspartic protease gene, a trypsin-like serine protease gene, a second subtilisin-like serine protease gene, and a second aspartic protease gene; and (b) identifying a mutant strain from step (a) wherein the one or more (several) genes are modified rendering the mutant strain deficient in the production of one or more (several) enzymes selected from the group consisting of a first subtilisin-like serine protease, a first aspartic protease, a trypsin-like serine protease, a second subtilisin-like serine protease, and a second aspartic protease, respectively, compared to the parent Trichoderma strain when cultivated under identical conditions.

An advantage of the present invention is elimination or reduction of one or more (several) enzyme activities, which may be detrimental to the production, downstream processing, e.g., recovery, and/or application of a particular polypeptide of interest.

In the methods of the present invention, the parent Trichoderma strain may be any Trichoderma strain such as a wild-type Trichoderma strain or a mutant thereof. The parent Trichoderma strain may be Trichoderma harzianum, Trichoderma koningii, Trichoderma longibrachiatum, Trichoderma reesei, or Trichoderma viride; or the alternative sexual form thereof, i.e., Hypocrea.

In another aspect, the parent Trichoderma strain is Trichoderma harzianum. In another aspect, the parent Trichoderma strain is Trichoderma koningii. In another aspect, the parent Trichoderma strain is Trichoderma longibrachiatum. In another aspect, the parent Trichoderma strain is Trichoderma reesei. In another aspect, the parent Trichoderma strain is Trichoderma viride.

In another aspect, the parent Trichoderma reesei strain is Trichoderma reesei RutC30. In another aspect, the parent Trichoderma reesei strain is Trichoderma reesei TV10. In another aspect, the parent Trichoderma reesei strain is a mutant of Trichoderma reesei. In another aspect, the parent Trichoderma reesei strain is a morphological mutant of Trichoderma reesei (see WO 97/26330).

The protease-deficient Trichoderma mutant strain may be constructed by reducing or eliminating expression of one or more (several) genes selected from the group consisting of a first subtilisin-like serine protease gene, a first aspartic protease gene, a trypsin-like serine protease gene, a second subtilisin-like serine protease gene, and a second aspartic protease gene using methods well known in the art, such as insertions, disruptions, replacements, or deletions. A portion of the gene can be modified such as the coding region or a control sequence required for expression of the coding region. Such a control sequence of the gene may be a promoter sequence or a functional part thereof, i.e., a part that is sufficient for affecting expression of the gene. For example, a promoter sequence may be inactivated resulting in no expression or a weaker promoter may be substituted for the native promoter sequence to reduce expression of the coding sequence. Other control sequences for possible modification include, but are not limited to, a leader, propeptide sequence, signal sequence, transcription terminator, and transcriptional activator.

The Trichoderma mutant strains may be constructed by gene deletion techniques to eliminate or reduce expression of the gene. Gene deletion techniques enable the partial or complete removal of the gene thereby eliminating their expression. In such methods, deletion of the gene is accomplished by homologous recombination using a plasmid that has been constructed to contiguously contain the 5′ and 3′ regions flanking the gene.

The Trichoderma mutant strains may also be constructed by introducing, substituting, and/or removing one or more (several) nucleotides in the gene or a control sequence thereof required for the transcription or translation thereof. For example, nucleotides may be inserted or removed for the introduction of a stop codon, the removal of the start codon, or a frame-shift of the open reading frame. Such a modification may be accomplished by site-directed mutagenesis or PCR generated mutagenesis in accordance with methods known in the art. See, for example, Botstein and Shortle, 1985, Science 229: 4719; Lo et al., 1985, Proceedings of the National Academy of Sciences USA 81: 2285; Higuchi et al., 1988, Nucleic Acids Research 16: 7351; Shimada, 1996, Meth. Mol. Biol. 57: 157; Ho et al., 1989, Gene 77: 61; Horton et al., 1989, Gene 77: 61; and Sarkar and Sommer, 1990, BioTechniques 8: 404.

The Trichoderma mutant strains may also be constructed by gene disruption techniques by inserting into the gene a disruptive nucleic acid construct comprising a nucleic acid fragment homologous to the gene that will create a duplication of the region of homology and incorporate construct DNA between the duplicated regions. Such a gene disruption can eliminate gene expression if the inserted construct separates the promoter of the gene from the coding region or interrupts the coding sequence such that a non-functional gene product results. A disrupting construct may be simply a selectable marker gene accompanied by 5′ and 3′ regions homologous to the gene. The selectable marker enables identification of transformants containing the disrupted gene.

The Trichoderma mutant strains may also be constructed by the process of gene conversion (see, for example, Iglesias and Trautner, 1983, Molecular General Genetics 189: 73-76). For example, in the gene conversion method, a nucleotide sequence corresponding to the gene is mutagenized in vitro to produce a defective nucleotide sequence, which is then transformed into the parent Trichoderma strain to produce a defective gene. By homologous recombination, the defective nucleotide sequence replaces the endogenous gene. It may be desirable that the defective nucleotide sequence also comprises a marker for selection of transformants containing the defective gene.

The Trichoderma mutant strains may also be constructed by established anti-sense techniques using a nucleotide sequence complementary to the nucleotide sequence of the gene (Parish and Stoker, 1997, FEMS Microbiology Letters 154: 151-157). More specifically, expression of the gene by a Trichoderma strain may be reduced or inactivated by introducing a nucleotide sequence complementary to the nucleotide sequence of the gene, which may be transcribed in the strain and is capable of hybridizing to the mRNA produced in the strain. Under conditions allowing the complementary anti-sense nucleotide sequence to hybridize to the mRNA, the amount of protein translated is thus reduced or eliminated.

The Trichoderma mutant strains may also be constructed by established RNA interference (RNAi) techniques (see, for example, WO 2005/056772 and WO 2008/080017).

The Trichoderma mutant strains may be further constructed by random or specific mutagenesis using methods well known in the art, including, but not limited to, chemical mutagenesis (see, for example, Hopwood, The Isolation of Mutants in Methods in Microbiology (J. R. Norris and D. W. Ribbons, eds.) pp. 363-433, Academic Press, New York, 1970). Modification of the gene may be performed by subjecting the parent strain to mutagenesis and screening for mutant strains in which expression of the gene has been reduced or inactivated. The mutagenesis, which may be specific or random, may be performed, for example, by use of a suitable physical or chemical mutagenizing agent, use of a suitable oligonucleotide, or subjecting the DNA sequence to PCR generated mutagenesis. Furthermore, the mutagenesis may be performed by use of any combination of these mutagenizing methods.

Examples of a physical or chemical mutagenizing agent suitable for the present purpose include ultraviolet (UV) irradiation, hydroxylamine, N-methyl-N′-nitro-N-nitrosoguanidine (MNNG), N-methyl-N′-nitrosogaunidine (NTG) O-methyl hydroxylamine, nitrous acid, ethyl methane sulphonate (EMS), sodium bisulphite, formic acid, and nucleotide analogues. When such agents are used, the mutagenesis is typically performed by incubating the parent strain to be mutagenized in the presence of the mutagenizing agent of choice under suitable conditions, and selecting for mutants exhibiting reduced or no expression of the gene.

In one aspect, the modification results in the inactivation of one or more (several) genes selected from the group consisting of a first subtilisin-like serine protease gene, a first aspartic protease gene, a trypsin-like serine protease gene, a second subtilisin-like serine protease gene, and a second aspartic protease gene. In another aspect, the modification results in a decrease in expression of one or more (several) genes selected from the group consisting of a first subtilisin-like serine protease gene, a first aspartic protease gene, a trypsin-like serine protease gene, a second subtilisin-like serine protease gene, and a second aspartic protease gene. In another aspect, the modification results in expression of one or more (several) genes selected from the group consisting of a first subtilisin-like serine protease gene, a first aspartic protease gene, a trypsin-like serine protease gene, a second subtilisin-like serine protease gene, and a second aspartic protease gene being decreased, inactivated, or a combination thereof.

In another aspect, the mutant comprises a modification of a first subtilisin-like serine protease gene. In another aspect, the mutant comprises a modification of a first aspartic protease gene. In another aspect, the mutant comprises a modification of a trypsin-like serine protease gene. In another aspect, the mutant comprises a modification of a second subtilisin-like serine protease gene. In another aspect, the mutant comprises a modification of a second aspartic protease gene.

In another aspect, the mutant comprises a modification of a first subtilisin-like serine protease gene and a first aspartic protease gene. In another aspect, the mutant comprises a modification of a first subtilisin-like serine protease gene and a trypsin-like serine protease gene. In another aspect, the mutant comprises a modification of a first subtilisin-like serine protease gene and a second subtilisin-like serine protease gene. In another aspect, the mutant comprises a modification of a first subtilisin-like serine protease gene and a second aspartic protease gene. In another aspect, the mutant comprises a modification of a first aspartic protease gene and a trypsin-like serine protease gene. In another aspect, the mutant comprises a modification of a first aspartic protease gene and a second subtilisin-like serine protease gene. In another aspect, the mutant comprises a modification of a first aspartic protease gene and a second aspartic protease gene. In another aspect, the mutant comprises a modification of a trypsin-like serine protease gene and a second subtilisin-like serine protease gene. In another aspect, the mutant comprises a modification of a trypsin-like serine protease gene and a second aspartic protease gene. In another aspect, the mutant comprises a modification of a second subtilisin-like serine protease gene and a second aspartic protease gene.

In another aspect, the mutant comprises a modification of a first subtilisin-like serine protease gene, a first aspartic protease gene, and a trypsin-like serine protease gene. In another aspect, the mutant comprises a modification of a first subtilisin-like serine protease gene, a trypsin-like serine protease gene, and a second subtilisin-like serine protease gene. In another aspect, the mutant comprises a modification of a first subtilisin-like serine protease gene, a second subtilisin-like serine protease gene, and a second aspartic protease gene. In another aspect, the mutant comprises a modification of a first subtilisin-like serine protease gene, a first aspartic protease gene, and a second subtilisin-like serine protease gene. In another aspect, the mutant comprises a modification of a first subtilisin-like serine protease gene, a first aspartic protease gene, and a second aspartic protease gene. In another aspect, the mutant comprises a modification of a first subtilisin-like serine protease gene, a trypsin-like serine protease gene, and a second aspartic protease gene. In another aspect, the mutant comprises a modification of a first aspartic protease gene, a trypsin-like serine protease gene, and a second subtilisin-like serine protease gene. In another aspect, the mutant comprises a modification of a first aspartic protease gene, a second subtilisin-like serine protease gene, and a second aspartic protease gene. In another aspect, the mutant comprises a modification of a first aspartic protease gene, a trypsin-like serine protease gene, and a second aspartic protease gene. In another aspect, the mutant comprises a modification of a trypsin-like serine protease gene, a second subtilisin-like serine protease gene, and a second aspartic protease gene.

In another aspect, the mutant comprises a modification of a first subtilisin-like serine protease gene, a first aspartic protease gene, a trypsin-like serine protease gene, and a second subtilisin-like serine protease gene. In another aspect, the mutant comprises a modification of a first subtilisin-like serine protease gene, a trypsin-like serine protease gene, a second subtilisin-like serine protease gene, and a second aspartic protease gene. In another aspect, the mutant comprises a modification of a first aspartic protease gene, a trypsin-like serine protease gene, a second subtilisin-like serine protease gene, and a second aspartic protease gene. In another aspect, the mutant comprises a modification of a first subtilisin-like serine protease gene, a first aspartic protease gene, a second subtilisin-like serine protease gene, and a second aspartic protease gene. In another aspect, the mutant comprises a modification of a first subtilisin-like serine protease gene, a first aspartic protease gene, a trypsin-like serine protease gene, and a second aspartic protease gene.

In another aspect, the mutant comprises a modification of a first subtilisin-like serine protease gene, a first aspartic protease gene, a trypsin-like serine protease gene, a second subtilisin-like serine protease gene, and a second aspartic protease gene.

In one aspect, the first subtilisin-like serine protease gene encodes a polypeptide having subtilisin-like serine protease activity comprising or consisting of an amino acid sequence having at least 60%, e.g., at least 65%, at least 70%, at least 75%, at least 80%, at least 85%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99%, or 100% sequence identity to SEQ ID NO: 2 or the mature polypeptide thereof. In another aspect, the first subtilisin-like serine protease gene encodes a polypeptide having subtilisin-like serine protease activity comprising or consisting of SEQ ID NO: 2. In another aspect, the first subtilisin-like serine protease gene encodes a polypeptide having subtilisin-like serine protease activity comprising or consisting of the mature polypeptide of SEQ ID NO: 2.

In another aspect, the first subtilisin-like serine protease gene comprises a polynucleotide comprising or consisting of a nucleotide sequence having at least 60%, e.g., e.g., at least 65%, at least 70%, at least 75%, at least 80%, at least 85%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99%, or 100% sequence identity to SEQ ID NO: 1 or the mature polypeptide coding sequence thereof. In another aspect, the first subtilisin-like serine protease gene comprises a polynucleotide comprising or consisting of SEQ ID NO: 1. In another aspect, the first subtilisin-like serine protease gene comprises a polynucleotide comprising or consisting of the mature polypeptide coding sequence of SEQ ID NO: 1.

In another aspect, the first subtilisin-like serine protease gene comprises a polynucleotide that hybridizes under very low stringency conditions, low stringency conditions, medium stringency conditions, medium-high stringency conditions, high stringency conditions, or very high stringency conditions with (i) SEQ ID NO: 1; (ii) the mature polypeptide coding sequence of SEQ ID NO: 1, (iii) the cDNA sequence of (i) or (ii), or (iv) a full-length complementary strand of (i), (ii), or (iii).

In another aspect, the first subtilisin-like serine protease comprises or consists of an amino acid sequence having at least 60%, e.g., at least 65%, at least 70%, at least 75%, at least 80%, at least 85%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99%, or 100% sequence identity to SEQ ID NO: 2 or the mature polypeptide thereof. In another aspect, the first subtilisin-like serine protease comprises or consists of SEQ ID NO: 2. In another aspect, the first subtilisin-like serine protease comprises or consists of the mature polypeptide of SEQ ID NO: 2.

In another aspect, the first subtilisin-like serine protease is encoded by a polynucleotide comprising or consisting of a nucleotide sequence having at least 60%, e.g., at least 65%, at least 70%, at least 75%, at least 80%, at least 85%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99%, or 100% sequence identity to SEQ ID NO: 1 or the cDNA thereof, or the mature polypeptide coding sequence thereof. In another aspect, the first subtilisin-like serine protease is encoded by a polynucleotide comprising or consisting of SEQ ID NO: 1. In another aspect, the first subtilisin-like serine protease is encoded by a polynucleotide comprising or consisting of the mature polypeptide coding sequence of SEQ ID NO: 1.

In another aspect, the first subtilisin-like serine protease is encoded by a polynucleotide that hybridizes under very low stringency conditions, low stringency conditions, medium stringency conditions, medium-high stringency conditions, high stringency conditions, or very high stringency conditions with (i) SEQ ID NO: 1; (ii) the mature polypeptide coding sequence of SEQ ID NO: 1, (iii) the cDNA sequence of (i) or (ii), or (iv) a full-length complementary strand of (i), (ii), or (iii).

In another aspect, the first aspartic protease gene encodes a polypeptide having aspartic protease activity comprising or consisting of an amino acid sequence having at least 60%, e.g., at least 65%, at least 70%, at least 75%, at least 80%, at least 85%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99%, or 100% sequence identity to SEQ ID NO: 4 or the mature polypeptide thereof. In another aspect, the first aspartic protease gene encodes a polypeptide having aspartic protease activity comprising or consisting of SEQ ID NO: 4. In another aspect, the first aspartic protease gene encodes a polypeptide having aspartic protease activity comprising or consisting of the mature polypeptide of SEQ ID NO: 4.

In another aspect, the first aspartic protease gene comprises a polynucleotide comprising or consisting of a nucleotide sequence having at least 60%, e.g., at least 65%, at least 70%, at least 75%, at least 80%, at least 85%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99%, or 100% sequence identity to SEQ ID NO: 3 or the cDNA thereof, or the mature polypeptide coding sequence thereof. In another aspect, the first aspartic protease gene comprises or consists of SEQ ID NO: 3. In another aspect, the first aspartic protease gene comprises or consists of the mature polypeptide coding sequence of SEQ ID NO: 3.

In another aspect, the first aspartic protease gene comprises a polynucleotide that hybridizes under very low stringency conditions, low stringency conditions, medium stringency conditions, medium-high stringency conditions, high stringency conditions, or very high stringency conditions with (i) SEQ ID NO: 3; (ii) the mature polypeptide coding sequence of SEQ ID NO: 3, (iii) the cDNA sequence of (i) or (ii), or (iv) a full-length complementary strand of (i), (ii), or (iii).

In another aspect, the first aspartic protease comprises or consists of an amino acid sequence having at least 60%, e.g., at least 65%, at least 70%, at least 75%, at least 80%, at least 85%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99%, or 100% sequence identity to SEQ ID NO: 4 or the mature polypeptide thereof. In another aspect, the first aspartic protease comprises or consists of SEQ ID NO: 4. In another aspect, the first aspartic protease comprises or consists of the mature polypeptide of SEQ ID NO: 4.

In another aspect, the first aspartic protease is encoded by a polynucleotide comprising or consisting of a nucleotide sequence having at least 60%, e.g., at least 65%, at least 70%, at least 75%, at least 80%, at least 85%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99%, or 100% sequence identity to SEQ ID NO: 3 or the cDNA thereof, or the mature polypeptide coding sequence thereof. In another aspect, the first aspartic protease is encoded by a polynucleotide comprising or consisting of SEQ ID NO: 3. In another aspect, the first aspartic protease is encoded by a polynucleotide comprising or consisting of the mature polypeptide coding sequence of SEQ ID NO: 3.

In another aspect, the first aspartic protease is encoded by a polynucleotide that hybridizes under very low stringency conditions, low stringency conditions, medium stringency conditions, medium-high stringency conditions, high stringency conditions, or very high stringency conditions with (i) SEQ ID NO: 3; (ii) the mature polypeptide coding sequence of SEQ ID NO: 3, (iii) the cDNA sequence of (i) or (ii), or (iv) a full-length complementary strand of (i), (ii), or (iii).

In another aspect, the trypsin-like serine protease gene encodes a polypeptide having trypsin-like serine protease activity comprising or consisting of an amino acid sequence having at least 60%, e.g., at least 65%, at least 70%, at least 75%, at least 80%, at least 85%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99%, or 100% sequence identity to SEQ ID NO: 6 or the mature polypeptide thereof. In another aspect, the trypsin-like serine protease gene encodes a polypeptide having trypsin-like serine protease activity comprising or consisting of SEQ ID NO: 6. In another aspect, the trypsin-like serine protease gene encodes a polypeptide having trypsin-like serine protease activity comprising or consisting of the mature polypeptide of SEQ ID NO: 6.

In another aspect, the trypsin-like serine protease gene comprises a polynucleotide comprising or consisting of a nucleotide sequence having at least 60%, e.g., at least 65%, at least 70%, at least 75%, at least 80%, at least 85%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99%, or 100% sequence identity to SEQ ID NO: 5 or the cDNA thereof, or the mature polypeptide coding sequence thereof. In another aspect, the trypsin-like serine protease gene comprises a polynucleotide comprising or consisting of SEQ ID NO: 5. In another aspect, the trypsin-like serine protease gene comprises a polynucleotide comprising or consisting of the mature polypeptide coding sequence of SEQ ID NO: 5.

In another aspect, the trypsin-like serine protease gene comprises a polynucleotide that hybridizes under very low stringency conditions, low stringency conditions, medium stringency conditions, medium-high stringency conditions, high stringency conditions, or very high stringency conditions with (i) SEQ ID NO: 5; (ii) the mature polypeptide coding sequence of SEQ ID NO: 5, (iii) the cDNA sequence of (i) or (ii), or (iv) a full-length complementary strand of (i), (ii), or (iii).

In another aspect, the trypsin-like serine protease comprises or consists of an amino acid sequence having at least 60%, e.g., at least 65%, at least 70%, at least 75%, at least 80%, at least 85%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99%, or 100% sequence identity to SEQ ID NO: 6 or the mature polypeptide thereof. In another aspect, the first aspartic protease comprises or consists of SEQ ID NO: 6. In another aspect, the first aspartic protease comprises or consists of the mature polypeptide of SEQ ID NO: 6.

In another aspect, the trypsin-like serine protease is encoded by a polynucleotide comprising or consisting of a nucleotide sequence having at least 60%, e.g., at least 65%, at least 70%, at least 75%, at least 80%, at least 85%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99%, or 100% sequence identity to SEQ ID NO: 5 or the cDNA thereof, or the mature polypeptide coding sequence thereof. In another aspect, the trypsin-like serine protease is encoded by a polynucleotide comprising or consisting of SEQ ID NO: 5. In another aspect, the trypsin-like serine protease is encoded by a polynucleotide comprising or consisting of the mature polypeptide coding sequence of SEQ ID NO: 5.

In another aspect, the trypsin-like serine protease is encoded by a polynucleotide that hybridizes under very low stringency conditions, low stringency conditions, medium stringency conditions, medium-high stringency conditions, high stringency conditions, or very high stringency conditions with (i) SEQ ID NO: 5; (ii) the mature polypeptide coding sequence of SEQ ID NO: 5, (iii) the cDNA sequence of (i) or (ii), or (iv) a full-length complementary strand of (i), (ii), or (iii).

In another aspect, the second subtilisin-like serine protease gene encodes a polypeptide having subtilisin-like serine protease activity comprising or consisting of an amino acid sequence having at least 60%, e.g., at least 65%, at least 70%, at least 75%, at least 80%, at least 85%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99%, or 100% sequence identity to SEQ ID NO: 100 or the mature polypeptide thereof. In another aspect, the second subtilisin-like serine protease gene encodes a polypeptide having subtilisin-like serine protease activity comprising or consisting of SEQ ID NO: 100. In another aspect, the second subtilisin-like serine protease gene encodes a polypeptide having subtilisin-like serine protease activity comprising or consisting of the mature polypeptide of SEQ ID NO: 100.

In another aspect, the second subtilisin-like serine protease gene comprises a polynucleotide comprising or consisting of a nucleotide sequence having at least 60%, e.g., at least 65%, at least 70%, at least 75%, at least 80%, at least 85%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99%, or 100% sequence identity to SEQ ID NO: 99 or the cDNA thereof, or the mature polypeptide coding sequence thereof. In another aspect, the second subtilisin-like serine protease gene comprises or consists of SEQ ID NO: 99. In another aspect, the second subtilisin-like serine protease gene comprises or consists of the mature polypeptide coding sequence of SEQ ID NO: 99.

In another aspect, the second subtilisin-like serine protease gene comprises a polynucleotide that hybridizes under very low stringency conditions, low stringency conditions, medium stringency conditions, medium-high stringency conditions, high stringency conditions, or very high stringency conditions with (i) SEQ ID NO: 99; (ii) the mature polypeptide coding sequence of SEQ ID NO: 99, (iii) the cDNA sequence of (i) or (ii), or (iv) a full-length complementary strand of (i), (ii), or (iii).

In another aspect, the second subtilisin-like serine protease comprises or consists of an amino acid sequence having at least 60%, e.g., at least 65%, at least 70%, at least 75%, at least 80%, at least 85%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99%, or 100% sequence identity to SEQ ID NO: 100 or the mature polypeptide thereof. In another aspect, the second subtilisin-like serine protease comprises or consists of SEQ ID NO: 100. In another aspect, the second subtilisin-like serine protease comprises or consists of the mature polypeptide of SEQ ID NO: 100.

In another aspect, the second subtilisin-like serine protease is encoded by a polynucleotide comprising or consisting of a nucleotide sequence having at least 60%, e.g., at least 65%, at least 70%, at least 75%, at least 80%, at least 85%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99%, or 100% sequence identity to SEQ ID NO: 99 or the cDNA thereof, or the mature polypeptide coding sequence thereof. In another aspect, the second subtilisin-like serine protease is encoded by a polynucleotide comprising or consisting of SEQ ID NO: 99. In another aspect, the second subtilisin-like serine protease is encoded by a polynucleotide comprising or consisting of the mature polypeptide coding sequence of SEQ ID NO: 99.

In another aspect, the second subtilisin-like serine protease is encoded by a polynucleotide that hybridizes under very low stringency conditions, low stringency conditions, medium stringency conditions, medium-high stringency conditions, high stringency conditions, or very high stringency conditions with (i) SEQ ID NO: 99; (ii) the mature polypeptide coding sequence of SEQ ID NO: 99, (iii) the cDNA sequence of (i) or (ii), or (iv) a full-length complementary strand of (i), (ii), or (iii).

In one aspect, the second aspartic protease gene encodes a polypeptide having aspartic protease activity comprising or consisting of an amino acid sequence having at least 60%, e.g., at least 65%, at least 70%, at least 75%, at least 80%, at least 85%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99%, or 100% sequence identity to SEQ ID NO: 108 or the mature polypeptide thereof. In another aspect, the second aspartic protease gene encodes a polypeptide having aspartic protease activity comprising or consisting of SEQ ID NO: 108. In another aspect, the second aspartic protease gene encodes a polypeptide having aspartic protease activity comprising or consisting of the mature polypeptide of SEQ ID NO: 108.

In another aspect, the second aspartic protease gene comprises a polynucleotide comprising or consisting of a nucleotide sequence having at least 60%, e.g., at least 65%, at least 70%, at least 75%, at least 80%, at least 85%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99%, or 100% sequence identity to SEQ ID NO: 107 or the cDNA thereof, or the mature polypeptide coding sequence thereof. In another aspect, the second aspartic protease gene comprises or consists of SEQ ID NO: 107. In another aspect, the second aspartic protease gene comprises or consists of the mature polypeptide coding sequence of SEQ ID NO: 107.

In another aspect, the second aspartic protease gene comprises a polynucleotide that hybridizes under very low stringency conditions, low stringency conditions, medium stringency conditions, medium-high stringency conditions, high stringency conditions, or very high stringency conditions with (i) SEQ ID NO: 107; (ii) the mature polypeptide coding sequence of SEQ ID NO: 107, (iii) the cDNA sequence of (i) or (ii), or (iv) a full-length complementary strand of (i), (ii), or (iii).

In another aspect, the second aspartic protease comprises or consists of an amino acid sequence having at least 60%, e.g., at least 65%, at least 70%, at least 75%, at least 80%, at least 85%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99%, or 100% sequence identity to SEQ ID NO: 108 or the mature polypeptide thereof. In another aspect, the second aspartic protease comprises or consists of SEQ ID NO: 108. In another aspect, the second aspartic protease comprises or consists of the mature polypeptide of SEQ ID NO: 108.

In another aspect, the second aspartic protease is encoded by a polynucleotide comprising or consisting of a nucleotide sequence having at least 60%, e.g., at least 65%, at least 70%, at least 75%, at least 80%, at least 85%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99%, or 100% sequence identity to SEQ ID NO: 107 or the cDNA thereof, or the mature polypeptide coding sequence thereof. In another aspect, the second aspartic protease is encoded by a polynucleotide comprising or consisting of SEQ ID NO: 107. In another aspect, the second aspartic protease is encoded by a polynucleotide comprising or consisting of the mature polypeptide coding sequence of SEQ ID NO: 107.

In another aspect, the second aspartic protease is encoded by a polynucleotide that hybridizes under very low stringency conditions, low stringency conditions, medium stringency conditions, medium-high stringency conditions, high stringency conditions, or very high stringency conditions with (i) SEQ ID NO: 107; (ii) the mature polypeptide coding sequence of SEQ ID NO: 107, (iii) the cDNA sequence of (i) or (ii), or (iv) a full-length complementary strand of (i), (ii), or (iii).

The nucleotide sequences disclosed herein or subsequences thereof, as well as the amino acid sequences thereof or fragments thereof, may be used to design nucleic acid probes to identify and clone homologous DNA of the genes described above from strains of different genera or species according to methods well known in the art. In particular, such probes can be used for hybridization with the genomic DNA or cDNA of the genus or species of interest, following standard Southern blotting procedures, in order to identify and isolate the corresponding gene therein. Such probes can be considerably shorter than the entire sequence, but should be at least 14, e.g., at least 25, at least 35, or at least 70 nucleotides in length. Preferably, the nucleic acid probe is at least 100 nucleotides in length, e.g., at least 200 nucleotides, at least 300 nucleotides, at least 400 nucleotides, at least 500 nucleotides, at least 600 nucleotides, at least 700 nucleotides, at least 800 nucleotides, or at least 900 nucleotides in length. Both DNA and RNA probes can be used. The probes are typically labeled for detecting the corresponding gene (for example, with ³²P, ³H, ³⁵S, biotin, or avidin).

Thus, a genomic DNA or cDNA library prepared from such other organisms may be screened for DNA that hybridizes with the probes described above. Genomic or other DNA from such other organisms may be separated by agarose or polyacrylamide gel electrophoresis, or other separation techniques. DNA from the libraries or the separated DNA may be transferred to and immobilized on nitrocellulose or other suitable carrier material. In order to identify a clone or DNA that is homologous with the nucleotide sequences disclosed herein or subsequences thereof, the carrier material is used in a Southern blot. For purposes of the present invention, hybridization indicates that the nucleic acid sequence hybridizes to a labeled nucleic acid probe corresponding to the nucleotide sequences disclosed herein, its complementary strand, or a subsequence thereof, under very low to very high stringency conditions. Molecules to which the nucleic acid probe hybridizes under these conditions are detected using X-ray film.

For long probes of at least 100 nucleotides in length, very low to very high stringency conditions are defined as prehybridization and hybridization at 42° C. in 5×SSPE, 0.3% SDS, 200 micrograms/ml sheared and denatured salmon sperm DNA, and either 25% formamide for very low and low stringencies, 35% formamide for medium and medium-high stringencies, or 50% formamide for high and very high stringencies, following standard Southern blotting procedures for 12 to 24 hours optimally. The carrier material is finally washed three times each for 15 minutes using 2×SSC, 0.2% SDS at 45° C. (very low stringency), at 50° C. (low stringency), at 55° C. (medium stringency), at 60° C. (medium-high stringency), at 65° C. (high stringency), and at 70° C. (very high stringency).

For short probes of about 15 nucleotides to about 70 nucleotides in length, stringency conditions are defined as prehybridization and hybridization at about 5° C. to about 10° C. below the calculated T_(m) using the calculation according to Bolton and McCarthy (1962, Proc. Natl. Acad. Sci. USA 48:1390) in 0.9 M NaCl, 0.09 M Tris-HCl pH 7.6, 6 mM EDTA, 0.5% NP-40, 1×Denhardt's solution, 1 mM sodium pyrophosphate, 1 mM sodium monobasic phosphate, 0.1 mM ATP, and 0.2 mg of yeast RNA per ml following standard Southern blotting procedures for 12 to 24 hours optimally. The carrier material is finally washed once in 6×SCC plus 0.1% SDS for 15 minutes and twice each for 15 minutes using 6×SSC at 5° C. to 10° C. below the calculated T_(m).

A nucleotide sequence homologous or complementary to a gene described herein may be used from other microbial sources to modify the corresponding gene in a Trichoderma strain of choice.

In another aspect, the modification of a gene in the Trichoderma mutant strain is unmarked with a selectable marker. Removal of the selectable marker gene may be accomplished by culturing the mutants on a counter-selection medium. Where the selectable marker gene contains repeats flanking its 5′ and 3′ ends, the repeats will facilitate the looping out of the selectable marker gene by homologous recombination when the mutant strain is submitted to counter-selection. The selectable marker gene may also be removed by homologous recombination by introducing into the mutant strain a nucleic acid fragment comprising 5′ and 3′ regions of the defective gene, but lacking the selectable marker gene, followed by selecting on the counter-selection medium. By homologous recombination, the defective gene containing the selectable marker gene is replaced with the nucleic acid fragment lacking the selectable marker gene. Other methods known in the art may also be used.

It will be understood that the methods of the present invention are not limited to a particular order for obtaining the Trichoderma mutant strain. The modification of a gene may be introduced into the parent strain at any step in the construction of the strain for the production of a polypeptide of interest. It is preferred that the Trichoderma mutant strain has already been made protease-deficient prior to such a construction.

In a further aspect of the present invention, the mutants of Trichoderma strains may contain additional modifications, e.g., deletions or disruptions, of other genes, which may encode substances detrimental to the production, recovery, or application of a polypeptide of interest.

In one aspect, the Trichoderma strain further comprises a modification, e.g., disruption or deletion, of one or more (several) genes encoding a proteolytic activity selected from the group consisting of an aminopeptidase, dipeptidylaminopeptidase, tripeptidylaminopeptidase, carboxypeptidase, metalloprotease, cysteine protease, and vacuolar protease.

In another aspect, the Trichoderma strain further comprises a modification, e.g., disruption or deletion, of one or more (several) additional genes encoding an oxidoreductase, a transferase, a hydrolase, a lyase, an isomerase, or a ligase.

In another aspect, the Trichoderma strain further comprises a modification, e.g., disruption or deletion, of one or more (several) additional genes encoding an enzyme selected from the group consisting of an alpha-amylase, arabinofuranosidase, carbohydrase, catalase, cellobiohydrolase, cellulase, chitinase, cyclodextrin glycosyltransferase, cutinase, cyclodextrin glycosyltransferase, deoxyribonuclease, endoglucanase, esterase, alpha-galactosidase, beta-galactosidase, glucocerebrosidase, glucose oxidase, alpha-glucosidase, beta-glucosidase, glucuronidases, haloperoxidase, hemicellulase, invertase, isomerase, laccase, ligase, lipase, mannosidase, mutanase, oxidase, pectinolytic enzyme, peroxidase, phospholipase, phytase, phenoloxidase, polyphenoloxidase, ribonuclease, alpha-1,6-transglucosidase, transglutaminase, urokinase, xylanase, and beta-xylosidase.

In another aspect, the Trichoderma strain further comprises a modification, e.g., disruption or deletion, of one or more (several) additional genes encoding an enzyme selected from the group consisting of an endoglucanase, a cellobiohydrolase, and a beta-glucosidase.

In the methods of the present invention, the Trichoderma mutant strain preferably produces at least the same amount of a biologically active polypeptide of interest as the corresponding parent Trichoderma strain when cultured under identical production conditions. In another aspect, the mutant strain produces preferably at least 5% more, more preferably at least 10% more, more preferably at least 25% more, more preferably at least 50% more, even more preferably at least 75% more, and most preferably at least 100% more of the biologically active polypeptide than the corresponding parent Trichoderma strain when cultured under identical production conditions.

The Trichoderma mutant strains are cultivated in a nutrient medium for production of the polypeptide of interest using methods known in the art. For example, the strain may be cultivated by shake flask cultivation, small-scale or large-scale fermentation (including continuous, batch, fed-batch, or solid state fermentations) in laboratory or industrial fermentors performed in a suitable medium and under conditions allowing the polypeptide to be expressed and/or isolated. The cultivation takes place in a suitable nutrient medium comprising carbon and nitrogen sources and inorganic salts, using procedures known in the art. Suitable media are available from commercial suppliers or may be prepared according to published compositions (e.g., in catalogues of the American Type Culture Collection). The secreted polypeptide can be recovered directly from the medium. If the polypeptide is not secreted, it may be obtained from cell lysates.

The polypeptide of interest may be detected using methods known in the art that are specific for the polypeptide. These detection methods may include use of specific antibodies, high performance liquid chromatography, capillary chromatography, formation of an enzyme product, disappearance of an enzyme substrate, or SDS-PAGE. For example, an enzyme assay may be used to determine the activity of an enzyme. Procedures for determining enzyme activity are known in the art for many enzymes (see, for example, D. Schomburg and M. Salzmann (eds.), Enzyme Handbook, Springer-Verlag, New York, 1990).

The resulting polypeptide may be isolated by methods known in the art. For example, a polypeptide of interest may be isolated from the cultivation medium by conventional procedures including, but not limited to, centrifugation, filtration, extraction, spray-drying, evaporation, or precipitation. The isolated polypeptide may then be further purified by a variety of procedures known in the art including, but not limited to, chromatography (e.g., ion exchange, affinity, hydrophobic, chromatofocusing, and size exclusion), electrophoretic procedures (e.g., preparative isoelectric focusing (IEF), differential solubility (e.g., ammonium sulfate precipitation), or extraction (see, e.g., Protein Purification, J.-C. Janson and Lars Ryden, editors, VCH Publishers, New York, 1989).

The polypeptide of interest may be any polypeptide native or foreign (heterologous) to the Trichoderma strain. The polypeptide may be encoded by a single gene or two or more genes. The term “polynucleotide encoding the polypeptide” will be understood to encompass one or more (several) genes involved in the production of the polypeptide. The term “heterologous polypeptide” is defined herein as a polypeptide that is not native to the host strain; a native polypeptide in which structural modifications have been made to alter the native polypeptide, e.g., the protein sequence of a native polypeptide; or a native polypeptide whose expression is quantitatively altered as a result of a manipulation of the polynucleotide or host strain by recombinant DNA techniques, e.g., a stronger promoter, multiple copies of a DNA encoding the polypeptide. Thus, the present invention also encompasses, within the scope of the term “heterologous polypeptides,” such recombinant production of native polypeptides, to the extent that such expression involves the use of genetic elements not native to the Trichoderma strain, or use of native elements that have been manipulated to function in a manner that do not normally occur in the host strain. In one aspect, the polypeptide is a native polypeptide to the Trichoderma strain. In another aspect, the polypeptide is a heterologous polypeptide to the Trichoderma strain.

The polypeptide may be any polypeptide having a biological activity of interest. The term “polypeptide” is not meant herein to refer to a specific length of the encoded product and, therefore, encompasses peptides, oligopeptides, and proteins. The term “polypeptide” also encompasses two or more polypeptides combined to form the encoded product. Polypeptides also include fusion polypeptides, which comprise a combination of partial or complete polypeptide sequences obtained from at least two different polypeptides wherein one or more (several) may be heterologous to the Trichoderma strain. Polypeptides further include naturally occurring allelic and engineered variations of the above-mentioned polypeptides and hybrid polypeptides.

In one aspect, the polypeptide is an antibody, an antigen, an antimicrobial peptide, an enzyme, a growth factor, a hormone, an immunodilator, a neurotransmitter, a receptor, a reporter protein, a structural protein, or a transcription factor.

In another aspect, the polypeptide is an oxidoreductase, a transferase, a hydrolase, a lyase, an isomerase, or a ligase. In another aspect, the polypeptide is an acetylmannan esterase, acetyxylan esterase, aminopeptidase, alpha-amylase, arabinanase, arabinofuranosidase, carbohydrase, carboxypeptidase, catalase, cellobiohydrolase, cellulase, chitinase, coumaric acid esterase, cyclodextrin glycosyltransferase, cutinase, cyclodextrin glycosyltransferase, deoxyribonuclease, endoglucanase, esterase, feruloyl esterase, GH61 polypeptide having cellulolytic enhancing activity, alpha-galactosidase, beta-galactosidase, glucocerebrosidase, glucose oxidase, alpha-glucosidase, beta-glucosidase, glucuronidase, glucuronoyl esterase, haloperoxidase, hemicellulase, invertase, isomerase, laccase, ligase, lipase, mannanase, mannosidase, mutanase, oxidase, pectinolytic enzyme, peroxidase, phospholipase, phytase, phenoloxidase, polyphenoloxidase, proteolytic enzyme, ribonuclease, alpha-1,6-transglucosidase, transglutaminase, urokinase, xylanase, or beta-xylosidase.

In another aspect, the polypeptide is an albumin, a collagen, a tropoelastin, an elastin, or a gelatin.

In another aspect, the polypeptide is an endoglucanase. In another aspect, the polypeptide is a cellobiohydrolase. In another aspect, the polypeptide is a beta-glucosidase. In another aspect, the polypeptide is a GH61 polypeptide having cellulolytic enhancing activity. In another aspect, the polypeptide is a xylanase. In another aspect, the polypeptide is a beta-xylosidase. In another aspect, the polypeptide is an acetyxylan esterase. In another aspect, the polypeptide is a feruloyl esterase. In another aspect, the polypeptide is an arabinofuranosidase. In another aspect, the polypeptide is a glucuronidase. In another aspect, the polypeptide is an acetylmannan esterase. In another aspect, the polypeptide is an arabinanase. In another aspect, the polypeptide is a coumaric acid esterase. In another aspect, the polypeptide is a galactosidase. In another aspect, the polypeptide is a glucuronoyl esterase. In another aspect, the polypeptide is a mannanase. In another aspect, the polypeptide is a mannosidase.

In the methods of the present invention, the mutant of the Trichoderma strain is a recombinant strain, comprising a polynucleotide encoding a heterologous polypeptide, which is advantageously used in the recombinant production of the polypeptide. The strain is preferably transformed with a vector comprising the polynucleotide encoding the heterologous polypeptide followed by integration of the vector into the chromosome. “Transformation” means introducing a vector comprising the polynucleotide into a host strain so that the vector is maintained as a chromosomal integrant or as a self-replicating extra-chromosomal vector. Integration is generally considered to be an advantage as the polynucleotide is more likely to be stably maintained in the strain. Integration of the vector into the chromosome can occur by homologous recombination, non-homologous recombination, or transposition.

The polynucleotide encoding a heterologous polypeptide may be obtained from any prokaryotic, eukaryotic, or other source, e.g., archaeabacteria. For purposes of the present invention, the term “obtained from” as used herein in connection with a given source shall mean that the polypeptide is produced by the source or by a strain in which a gene from the source has been inserted.

In the methods of the present invention, the polypeptide may also be a fused polypeptide or cleavable fusion polypeptide in which another polypeptide is fused at the N-terminus or the C-terminus of the polypeptide of the present invention. A fused polypeptide is produced by fusing a polynucleotide encoding another polypeptide to a polynucleotide of the present invention. Techniques for producing fusion polypeptides are known in the art, and include ligating the coding sequences encoding the polypeptides so that they are in frame and that expression of the fused polypeptide is under control of the same promoter(s) and terminator. Fusion proteins may also be constructed using intein technology in which fusions are created post-translationally (Cooper et al., 1993, EMBO J. 12: 2575-2583; Dawson et al., 1994, Science 266: 776-779).

A fusion polypeptide can further comprise a cleavage site between the two polypeptides. Upon secretion of the fusion protein, the site is cleaved releasing the two polypeptides. Examples of cleavage sites include, but are not limited to, the sites disclosed in Martin et al., 2003, J. Ind. Microbiol. Biotechnol. 3: 568-576; Svetina et al., 2000, J. Biotechnol. 76: 245-251; Rasmussen-Wilson et al., 1997, Appl. Environ. Microbiol. 63: 3488-3493; Ward et al., 1995, Biotechnology 13: 498-503; and Contreras et al., 1991, Biotechnology 9: 378-381; Eaton et al., 1986, Biochemistry 25: 505-512; Collins-Racie et al., 1995, Biotechnology 13: 982-987; Carter et al., 1989, Proteins: Structure, Function, and Genetics 6: 240-248; and Stevens, 2003, Drug Discovery World 4: 35-48.

In the methods of the present invention, a mutant Trichoderma strain of the present invention may also be used for the recombinant production of a polypeptide that is native to the Trichoderma strain. The native polypeptide may be produced by recombinant means by, for example, placing a gene encoding the polypeptide under the control of a different promoter to enhance expression of the substance, expediting its export outside the strain by use of, for example, a signal sequence, or increasing the copy number of a gene encoding the polypeptide normally produced by the Trichoderma strain.

The techniques used to isolate or clone a polynucleotide encoding a polypeptide of interest are known in the art and include isolation from genomic DNA, preparation from cDNA, or a combination thereof. The cloning of such a polynucleotide from such genomic DNA can be effected, e.g., by using the well known polymerase chain reaction (PCR). See, for example, Innis et al., 1990, PCR Protocols: A Guide to Methods and Application, Academic Press, New York. The cloning procedures may involve excision and isolation of a desired nucleic acid fragment comprising the polynucleotide encoding the polypeptide, insertion of the fragment into a vector molecule, and incorporation of the recombinant vector into a mutant Trichoderma strain of the present invention where multiple copies or clones of the polynucleotide will be replicated. The polynucleotide may be of genomic, cDNA, RNA, semisynthetic, synthetic origin, or any combinations thereof.

An isolated polynucleotide encoding a heterologous polypeptide may be manipulated in a variety of ways to provide for expression of the polypeptide in a mutant Trichoderma strain of the present invention. Manipulation of the polynucleotide's sequence prior to its insertion into a vector may be desirable or necessary depending on the expression vector. The techniques for modifying polynucleotide sequences utilizing recombinant DNA methods are well known in the art.

A nucleic acid construct comprising a polynucleotide encoding a polypeptide may be operably linked to one or more (several) control sequences capable of directing expression of the coding sequence in a mutant Trichoderma strain of the present invention under conditions compatible with the control sequences.

The control sequence may be an appropriate promoter sequence, a nucleotide sequence that is recognized by a mutant Trichoderma strain of the present invention for expression of the polynucleotide encoding the polypeptide. The promoter sequence contains transcriptional control sequences that mediate expression of the polypeptide. The promoter may be any nucleotide sequence that shows transcriptional activity in the mutant Trichoderma strain, including mutant, truncated, and hybrid promoters, and may be obtained from genes encoding extracellular or intracellular polypeptides either native or heterologous (foreign) to the mutant Trichoderma strain.

Examples of suitable promoters for directing the transcription of the nucleic acid constructs in the methods of the present invention are promoters obtained from the genes for Aspergillus oryzae TAKA amylase, Rhizomucor miehei aspartic proteinase, Aspergillus niger neutral alpha-amylase, Aspergillus niger acid stable alpha-amylase, Aspergillus niger or Aspergillus awamori glucoamylase (glaA), Rhizomucor miehei lipase, Aspergillus oryzae alkaline protease, Aspergillus oryzae triose phosphate isomerase, Aspergillus nidulans acetamidase, Fusarium venenatum amyloglucosidase (WO 00/56900), Fusarium venenatum Daria (WO 00/56900), Fusarium venenatum Quinn (WO 00/56900), Fusarium oxysporum trypsin-like protease (WO 96/00787), Trichoderma reesei beta-glucosidase, Trichoderma reesei cellobiohydrolase I, Trichoderma reesei cellobiohydrolase II, Trichoderma reesei endoglucanase I, Trichoderma reesei endoglucanase II, Trichoderma reesei endoglucanase III, Trichoderma reesei endoglucanase V, Trichoderma reesei xylanase I, Trichoderma reesei xylanase II, Trichoderma reesei beta-xylosidase, as well as the NA2-tpi promoter (a modified promoter including a gene encoding a neutral alpha-amylase in Aspergilli in which the untranslated leader has been replaced by an untranslated leader from a gene encoding triose phosphate isomerase in Aspergilli; non-limiting examples include modified promoters including the gene encoding neutral alpha-amylase in Aspergillus niger in which the untranslated leader has been replaced by an untranslated leader from the gene encoding triose phosphate isomerase in Aspergillus nidulans or Aspergillus oryzae); and mutant, truncated, and hybrid promoters thereof.

The control sequence may also be a suitable transcription terminator sequence, a sequence recognized by a mutant Trichoderma strain of the present invention to terminate transcription. The terminator sequence is operably linked to the 3′ terminus of the nucleotide sequence encoding the heterologous polypeptide. Any terminator that is functional in a Trichoderma strain may be used in the present invention.

Preferred terminators are obtained from the genes for Aspergillus oryzae TAKA amylase, Aspergillus niger glucoamylase, Aspergillus nidulans anthranilate synthase, Aspergillus niger alpha-glucosidase, and Fusarium oxysporum trypsin-like protease.

The control sequence may also be a suitable leader sequence, a nontranslated region of a mRNA that is important for translation by a mutant Trichoderma strain of the present invention. The leader sequence is operably linked to the 5′ terminus of the nucleotide sequence encoding the heterologous polypeptide. Any leader sequence that is functional in the mutant Trichoderma strain may be used in the present invention.

Preferred leaders for filamentous fungal host cells are obtained from the genes for Aspergillus oryzae TAKA amylase and Aspergillus nidulans triose phosphate isomerase.

The control sequence may also be a polyadenylation sequence, a sequence operably linked to the 3′ terminus of the nucleotide sequence and, when transcribed, is recognized by the mutant Trichoderma strain as a signal to add polyadenosine residues to transcribed mRNA. Any polyadenylation sequence that is functional in the mutant Trichoderma strain may be used in the present invention.

Preferred polyadenylation sequences for filamentous fungal host cells are obtained from the genes for Aspergillus oryzae TAKA amylase, Aspergillus niger glucoamylase, Aspergillus nidulans anthranilate synthase, Fusarium oxysporum trypsin-like protease, and Aspergillus niger alpha-glucosidase.

The control sequence may also be a signal peptide coding sequence that codes for an amino acid sequence linked to the amino terminus of a polypeptide and directs the encoded polypeptide into the cell's secretory pathway. The 5′ end of the coding sequence of the nucleotide sequence may inherently contain a signal peptide coding sequence naturally linked in translation reading frame with the segment of the coding sequence that encodes the secreted polypeptide. Alternatively, the 5′ end of the coding sequence may contain a signal peptide coding sequence that is foreign to the coding sequence. The foreign signal peptide coding sequence may be required where the coding sequence does not naturally contain a signal peptide coding sequence. Alternatively, the foreign signal peptide coding sequence may simply replace the natural signal peptide coding sequence in order to enhance secretion of the polypeptide. However, any signal peptide coding sequence that directs the expressed polypeptide into the secretory pathway of the mutant Trichoderma strain, i.e., secreted into a culture medium, may be used in the present invention.

Effective signal peptide coding regions for the mutant Trichoderma strains are the signal peptide coding regions obtained from the genes for Aspergillus oryzae TAKA amylase, Aspergillus niger neutral amylase, Aspergillus niger glucoamylase, Rhizomucor miehei aspartic proteinase, Humicola insolens cellulase, Humicola insolens endoglucanase V, and Humicola lanuginosa lipase.

The control sequence may also be a propeptide coding region, which codes for an amino acid sequence positioned at the amino terminus of a polypeptide. The resultant polypeptide is known as a proenzyme or propolypeptide (or a zymogen in some cases). A propolypeptide is generally inactive and can be converted to a mature, active polypeptide by catalytic or autocatalytic cleavage of the propeptide from the propolypeptide. The propeptide coding region may be obtained from genes for Saccharomyces cerevisiae alpha-factor, Rhizomucor miehei aspartic proteinase, and Myceliophthora thermophila laccase (WO 95/33836).

Where both signal peptide and propeptide sequences are present at the amino terminus of a polypeptide, the propeptide sequence is positioned next to the amino terminus of a polypeptide and the signal peptide sequence is positioned next to the amino terminus of the propeptide sequence.

The nucleic acid constructs may also comprise one or more (several) polynucleotides that encode one or more (several) factors that are advantageous for directing expression of the heterologous polypeptide, e.g., a transcriptional activator (e.g., a trans-acting factor), a chaperone, and a processing protease. Any factor that is functional in the mutant Trichoderma strain may be used in the present invention. The nucleic acids encoding one or more (several) of these factors are not necessarily in tandem with the nucleotide sequence encoding the heterologous polypeptide.

It may also be desirable to add regulatory or control sequences that allow regulation of expression of the polypeptide relative to the growth of the mutant Trichoderma strain. Examples of regulatory systems are those that cause expression of the gene to be turned on or off in response to a chemical or physical stimulus, including the presence of a regulatory compound. Regulatory systems in filamentous fungi such as the TAKA alpha-amylase promoter, Aspergillus niger glucoamylase promoter, and Aspergillus oryzae glucoamylase promoter may be used as regulatory sequences. Other examples of regulatory sequences are those that allow for gene amplification. In eukaryotic systems, these regulatory sequences include the dihydrofolate reductase gene that is amplified in the presence of methotrexate, and the metallothionein genes that are amplified with heavy metals. In these cases, the nucleotide sequence encoding the polypeptide would be operably linked with the regulatory sequence.

In the methods of the present invention, a recombinant expression vector comprising a nucleotide sequence, a promoter, and transcriptional and translational stop signals may be used for the recombinant production of a polypeptide of interest. The various nucleic acids and control sequences described herein may be joined together to produce a recombinant expression vector that may include one or more (several) convenient restriction sites to allow for insertion or substitution of the nucleotide sequence encoding the polypeptide at such sites. Alternatively, the nucleotide sequence may be expressed by inserting the nucleotide sequence or a nucleic acid construct comprising the sequence into an appropriate vector for expression. In creating the expression vector, the coding sequence is located in the vector so that the coding sequence is operably linked with the appropriate control sequences for expression.

The recombinant expression vector may be any vector (e.g., a plasmid or virus) that can be conveniently subjected to recombinant DNA procedures and can bring about expression of the nucleotide sequence. The choice of the vector will typically depend on its compatibility with the mutant Trichoderma strain into which the vector is to be introduced. The vector may be a linear or closed circular plasmid.

The vector may be an autonomously replicating vector, i.e., a vector that exists as an extrachromosomal entity, the replication of which is independent of chromosomal replication, e.g., a plasmid, an extrachromosomal element, a minichromosome, or an artificial chromosome. The vector may contain any means for assuring self-replication. Alternatively, the vector may be one that, when introduced into the mutant Trichoderma strain, is integrated into the genome and replicated together with the chromosome(s) into which it has been integrated. Furthermore, a single vector or plasmid or two or more vectors or plasmids that together contain the total DNA to be introduced into the genome of the mutant Trichoderma strain, or a transposon, may be used.

The vector preferably contains one or more (several) selectable markers that permit easy selection of transformed mutant Trichoderma strains. A selectable marker is a gene the product of which provides for biocide or viral resistance, resistance to heavy metals, prototrophy to auxotrophs, and the like.

Examples of selectable markers for use in the mutant Trichoderma strain include, but are not limited to, amdS (acetamidase), argB (ornithine carbamoyltransferase), bar (phosphinothricin acetyltransferase), hpt (hygromycin phosphotransferase), niaD (nitrate reductase), pyrG (orotidine-5′-phosphate decarboxylase), sC (sulfate adenyltransferase), and trpC (anthranilate synthase), as well as equivalents thereof. Preferred for use in the mutant Trichoderma strain are the amdS gene of Aspergillus nidulans and the bar gene of Streptomyces hygroscopicus.

The vectors preferably contain an element(s) that permits integration of the vector into the host cell's genome or autonomous replication of the vector in the cell independent of the genome.

For integration into the genome of the mutant Trichoderma strain, the vector may rely on the polynucleotide's sequence encoding the polypeptide or any other element of the vector for integration into the genome by homologous or nonhomologous recombination. Alternatively, the vector may contain additional nucleotide sequences for directing integration by homologous recombination into the genome of the mutant Trichoderma strain at a precise location(s) in the chromosome(s). To increase the likelihood of integration at a precise location, the integrational elements should preferably contain a sufficient number of nucleic acids, such as 100 to 10,000 base pairs, preferably 400 to 10,000 base pairs, and most preferably 800 to 10,000 base pairs, which have a high degree of identity to the corresponding target sequence to enhance the probability of homologous recombination. The integrational elements may be any sequence that is homologous with the target sequence in the genome of the mutant Trichoderma strain. Furthermore, the integrational elements may be non-encoding or encoding nucleotide sequences. On the other hand, the vector may be integrated into the genome of the mutant Trichoderma strain by non-homologous recombination.

For autonomous replication, the vector may further comprise an origin of replication enabling the vector to replicate autonomously in the mutant Trichoderma strain. The origin of replication may be any plasmid replicator mediating autonomous replication that functions in a cell. The term “origin of replication” or “plasmid replicator” is defined herein as a nucleotide sequence that enables a plasmid or vector to replicate in vivo.

Examples of origins of replication useful in the mutant Trichoderma strain are AMA1 and ANS1 (Gems et al., 1991, Gene 98: 61-67; Cullen et al., 1987, Nucleic Acids Research 15: 9163-9175; WO 00/24883). Isolation of the AMA1 gene and construction of plasmids or vectors comprising the gene can be accomplished according to the methods disclosed in WO 00/24883.

The procedures used to ligate the elements described herein to construct the recombinant expression vectors are well known to one skilled in the art (see, e.g., J. Sambrook, E. F. Fritsch, and T. Maniatus, 1989, Molecular Cloning, A Laboratory Manual, 2d edition, Cold Spring Harbor, N.Y.).

A vector comprising the nucleotide sequence can be introduced, e.g., by transformation, into the mutant Trichoderma strain so that the vector is maintained as a chromosomal integrant or as a self-replicating extra-chromosomal vector. Integration is generally considered to be an advantage as the nucleotide sequence is more likely to be stably maintained in the strain. Integration of the vector into the chromosome occurs by homologous recombination, non-homologous recombination, or transposition.

The introduction of an expression vector into the mutant Trichoderma strain may involve a process consisting of protoplast formation, transformation of the protoplasts, and regeneration of the strain wall in a manner known per se. Suitable procedures for transformation of Trichoderma strains are described in Malardier et al., 1989, Gene 78: 147-156, and WO 96/00787.

The present invention is further described by the following examples that should not be construed as limiting the scope of the invention.

EXAMPLES

Strain

Trichoderma reesei strain 981-O-8 (D4) is a mutagenized strain of Trichoderma reesei RutC30 (ATCC 56765; Montenecourt and Eveleigh, 1979, Adv. Chem. Ser. 181: 289-301).

Media and Buffer Solutions

LB medium was composed of 10 g of tryptone, 5 g of yeast extract, and 5 g of sodium chloride, and deionized water to 1 liter.

LB plates were composed of 10 g of tryptone, 5 g of yeast extract, 5 g of NaCl, 15 g of Bacto agar, and deionized water to 1 liter.

PDA plates were composed of 39 g of Potato Dextrose Agar (Difco) and deionized water to 1 liter.

NZY top agarose was composed of 5 g of NaCl, 5 g of yeast extract, 10 g of NZ amine, 2 g of MgSO₄, 7 g of agarose, and deionized water to 1 liter.

YEG medium was composed of 5 g of yeast extract, 20 g of glucose, and deionized water to 1 liter.

2×YT agar plates were composed of 16 g of tryptone, 10 g of yeast extract, 5 g of sodium chloride, 15 g of Bactoagar, and deionized water to 1 liter.

Trichoderma minimal medium plates were composed of 30 g of sucrose, 20 ml of COVE salt solution, 0.6 g of CaCl₂.2H₂O, 6 g of (NH₄)₂SO₄, 25 g of Noble agar, and deionized water to 1 liter.

COVE plates were composed per liter of 342.3 g of sucrose, 25 g of Noble agar, 20 ml of COVE salts solution, 10 mM acetamide, and 15 or 20 mM CsCl. The solution was adjusted to pH 7.0 before autoclaving.

COVE2 plates were composed of 30 g of sucrose, 20 ml of COVE salt solution, 10 mM acetamide, 25 g or 30 g of Noble agar, and deionized water to 1 liter.

COVE salt solution was composed of 26 g of KCl, 26 g of MgSO₄.7H₂O, 76 g of KH₂PO₄, 50 ml of COVE trace metals solution, and deionized water to 1 liter.

COVE trace metals solution was composed of 0.04 g of NaB₄O₇.10H₂O, 0.4 g of CuSO₄.5H₂O, 1.2 g of FeSO₄.7H₂O, 0.7 g or 1 g of MnSO₄.H₂O, 0.8 g of Na₂MoO₂.2H₂O, 10 g of ZnSO₄.7H₂O, and deionized water to 1 liter.

COVE top agarose was composed of 342.3 g of sucrose, 20 ml of COVE salt solution, 10 mM acetamide, 10 g of low melt agarose, and deionized water to 1 liter.

Cellulase-inducing medium was composed of 20 g of Arbocel-natural cellulose fibers (J. Rettenmaier USA LP, Schoolcraft, Mich., USA), 10 g of corn steep solids (Sigma Chemical Co., St. Louis, Mo., USA), 1.45 g of (NH₄)₂SO₄, 2.08 g of KH₂PO₄, 0.28 g of CaCl₂, 0.42 g of MgSO₄.7H₂O, 0.42 ml of trace metals solution, 2 drops of pluronic acid, and deionized water to 1 liter. The pH was adjusted to 6.0 with 10 N NaOH before autoclaving.

Shake flask medium was composed of 20 g of dextrose, 10 g of corn steep solids, 1.45 g of (NH₄)₂SO₄, 2.08 g of KH₂PO₄, 0.36 g of CaCl₂, 0.42 g of MgSO₄.7H₂O, and 0.42 ml of trace metals solution.

Fermentation batch medium was composed per liter of 30 g of cellulose, 4 g of dextrose, 10 g of corn steep solids, 3.8 g of (NH₄)₂SO₄, 2.8 g of KH₂PO₄, 2.64 g of CaCl₂, 1.63 g of MgSO₄.7H₂O, 1.8 ml of anti-foam, 0.66 ml of trace metals solution, and deionized water to 1 liter.

Fermentation feed medium was composed of dextrose.

Trace metals solution was composed of 216 g of FeCl₃.6H₂O, 58 g of ZnSO₄.7H₂O, 27 g of MnSO₄—H₂O, 10 g of CuSO₄.5H₂O, 2.4 g of H₃BO₃, 336 g of citric acid, and deionized water to 1 liter.

YP medium was composed of 10 g of yeast extract, 20 g of Bacto peptone, and deionized water to 1 liter.

YP+2% glucose medium was composed of 1% yeast extract, 2% peptone and 2% glucose in deionized water.

YP+2% maltodextrin medium was composed of 2% peptone, 2% maltodextrin, and 1% yeast extract in deionized water.

DAP-2C-1 medium was composed of 2% glucose, 1.1% magnesium sulfate, 1.0% maltose, 0.52% tri-potassium phosphate, 0.2% citric acid, 0.1% potassium dihydrogen phosphate, 0.1% Dowfax 63N10, 0.05% yeast extract, and 0.05% of a trace element solution (1.39% ferrous sulfate, 0.845% maganese sulfate, 0.68% zinc chloride, 0.3% citric acid, 0.25% copper sulfate, and 0.013% nickel chloride) in deionized water.

PEG buffer was composed of 500 g of PEG 4000, 10 mM CaCl₂, 10 mM Tris-HCl pH 7.5, and deionized water to 1 liter; filter sterilized.

STC was composed of 0.8 M or 1 M sorbitol, 10 mM or 25 mM CaCl₂, and 10 mM or 25 mM Tris-HCl, pH 7.5 or pH 8; filter sterilized.

TE Buffer was composed of 1 M Tris pH 8.0 and 0.5 M EDTA pH 8.0

20×SSC was composed of 175.3 g NaCl, 88.2 g of sodium citrate, and deionized water to 1 liter.

Example 1: Construction of Plasmid pDM156.2

A probe of a Neurospora crassa orotidine-5′-monophosphate decarboxylase (pyr-4) gene (SEQ ID NO: 7 for the DNA sequence and SEQ ID NO: 8 for the deduced amino acid sequence) was prepared by PCR incorporating digoxigenin-labeled deoxyuridine-triphosphate (dUTP) using the primers described below.

Primer (sense): (SEQ ID NO: 9) 5′-GTCAGGAAACGCAGCCACAC-3′ Primer (anti-sense): (SEQ ID NO: 10) 5′-AGGCAGCCCTTGGACGACAT-3′

Plasmid pFB6 (Buxton et al, 1983, Molecular and General Genetics 190: 403-405) was digested with Hind III and the digestion purified by 1% agarose gel electrophoresis using 40 mM Tris base-20 mM sodium acetate-1 mM disodium EDTA (TAE) buffer. A 1.1 kb pyr-4 fragment was excised from the gel and extracted using a QIAQUICK® Gel Extraction Kit (QIAGEN Inc., Valencia Calif., USA) according to the manufacturer's suggested protocols.

The amplification reaction (50 μl) was composed of 1×Taq DNA Polymerase Buffer (New England Biolabs Inc., Ipswich, Mass., USA), 5 μl of PCR DIG Labeling Mix (Roche Molecular Biochemicals, Indianapolis, Ind., USA), 10 ng of the 1.1 kb Hind III pyr-4 fragment, 10 pmol of the sense primer, 10 pmol of the anti-sense primer, and 1 unit of Taq DNA polymerase (New England Biolabs Inc., Ipswich, Mass., USA). The reaction was incubated in a ROBOCYCLER® (Stratagene, La Jolla, Calif., USA) programmed for 1 cycle at 95° C. for 3 minutes followed by 35 cycles each at 95° C. for 30 seconds, 55° C. for 1 minute, and 72° C. for 1 minute. A final extension was performed for 5 minutes at 72° C.

The amplification reaction products were purified by 1% agarose gel electrophoresis using TAE buffer. A digoxigenin (DIG) labeled probe of approximately 0.78 kb was excised from the gel and extracted using a QIAQUICK® Gel Extraction Kit.

A genomic DNA library of Fusarium venenatum strain A3/5 was generated and cloned into lambda vector EMBL4 as described in WO 99/60137.

The DIG-labeled probe was used to screen the genomic library of Fusarium venenatum A3/5 DNA cloned into lambda vector EMBL4. Lambda phages were plated with E. coli K802 cells (New England Biolabs, Ipswich, Mass., USA) onto LB plates with NZY top agarose. Plaque lifts were made to HYBOND™ N nylon membranes (Amersham Biosciences, Buckinghamshire, UK) using the technique of Sambrook et al. (Molecular Cloning, A Laboratory Manual, Second Edition; J. Sambrook, E. F. Fritsch, and T. Maniatis; Cold Spring Harbor Laboratory Press, 1989). DNA was bound to the membranes by UV cross-linking using a UV STRATALINKER™ (Stratagene, La Jolla, Calif., USA). Filters were then hybridized with the 0.78 kb DIG-labeled N. crassa pyr-4 probe. Hybridization and detection of pyrG clones were performed according to the GENIUS™ System User's Guide (Boehringer Hammheim, Manheim, Germany) at 42° C. with a hybridization solution composed of 5×SSC, 35% formamide, 0.1% L-lauroylsarcosine, 0.02% SDS, and 1% blocking reagent (Boehringer Hammheim, Manheim, Germany). The concentration of DIG-labeled probe used was 2.5 ng per ml of the hybridization solution. Hybridizing DNA was immuno-detected with an alkaline-phosphatase-conjugated anti-digoxigenin antibody (Boehringer Hammheim, Manheim, Germany) and visualized with Lumiphos 530, a chemiluminescent substrate (Boehringer Hammheim, Manheim, Germany). DNA preparations were made from putative positive lambda clones using a Lambda Midi Kit (QIAGEN Inc., Valencia, Calif., USA).

Lambda DNA from a clone identified above was digested with Eco RI and subjected to 1% agarose gel electrophoresis in TAE buffer. A 3.9 kb fragment was excised and extracted using a QIAEX® Gel Extraction Kit (QIAGEN Inc., Valencia, Calif., USA). The fragment was then cloned into the Eco RI site of pUC18 (Viera and Messing, 1987, Methods in Enzymology 153: 3-11) and ONE SHOT® TOP10 competent cells (Invitrogen, Carlsbad, Calif., USA) were transformed with 2 μl of the cloning reaction. Plasmid DNA from eight of the resulting transformants was analyzed by DNA sequencing. One clone with the desired sequence was selected and designated pDM156.2 (FIG. 1). The pyrG fragment harbored the entire coding region plus 1.3 kb of the promoter and 1.5 kb of the terminator.

Example 2: Construction of Plasmid pEmY21

An E. coli hygromycin phosphotransferase (hpt) gene (SEQ ID NO: 11 for the DNA sequence and SEQ ID NO: 12 for the deduced amino acid sequence) was amplified from plasmid pPHTI (Cummings et al., 1999, Current Genetics 36: 371-382) using the following primers:

Forward primer: (SEQ ID NO: 13) 5′-GGGttcgaaTTCATTTAAACGGCT-3′ Reverse primer: (SEQ ID NO: 14) 5′-GGGagcgctCAATATTCATCTCTC-3′ The restriction enzyme sites Bst BI (forward primer) and Eco 47111 (reverse primer) were engineered into the primers, represented by the underlined sequence, for cloning.

The PCR reaction (to amplify the hpt gene) was composed of 1× ThermoPol reaction buffer (New England Biolabs, Inc, Ipswich, Mass., USA), 200 μM dNTPs, 50 pmol of the forward and reverse primers, 100 μg of pPHT1, 1 unit of VENT® DNA polymerase (New England Biolabs Inc., Ipswich, Mass. USA), and sterile distilled water in a total volume of 100 μl. The amplification reaction was performed using a ROBOCYCLER® programmed for 1 cycle at 95° C. for 2 minutes; 25 cycles each at 95° C. for 1 minute, 51° C. for 1 minute, and 72° C. for 2 minutes; and 1 cycle at 72° C. for 7 minutes.

PCR products were separated by 1% agarose gel electrophoresis in TAE buffer. A 1.8 kb fragment was excised from the gel and extracted using a QIAQUICK® Gel Extraction Kit. The gel purified fragment was then cloned into pCR®-BluntII-TOPO® (Invitrogen, Carlsbad, Calif., USA) using a TOPO® Blunt Cloning Kit (Invitrogen, Carlsbad, Calif., USA). The resulting plasmid was designated pEmY10.

The Eco RI site was then removed from the coding sequence of the hpt gene in pEmY10 using a QUIKCHANGE® Site-Directed Mutagenesis Kit (Stratagene, La Jolla, Calif., USA) according to the manufacturer's instructions using the primers shown below, where the lower case letters represent the non-mutated nucleotides of the target Eco RI site and the underlined case letters represent the mutated nucleotides. The resulting plasmid was designated pBK3.

Forward primer: (SEQ ID NO: 15) 5′-GGGTACCCCAAGGGCgTattcTGCAGATGGG-3′ Reverse primer: (SEQ ID NO: 16) 5′-CCCATCTGCAgaatAcGCCOTTGGGGTACCC-3′ The resulting hpt gene without the Eco RI site was PCR amplified from pBK3 using forward and reverse primers shown below.

Forward primer: (SEQ ID NO: 17) 5′-GGggtaccTTCATTTAAACGGCTTCAC-3′ Reverse primer: (SEQ ID NO: 18) 5′-GGggtaccCGACCAGCAGACGGCCC-3′ The underlined portions represent introduced Kpn I sites for cloning.

Portions of the Aspergillus oryzae pyrG gene were used to generate direct repeats and were PCR amplified from pSO2 (WO 98/12300) using the following primers:

Repeat 1: Forward primer: (SEQ ID NO: 19) 5′-TCCcccgggTCTCTGGTACTCTTCGATC-3′ Reverse primer: (SEQ ID NO: 20) 5′-GGggtaccCGACCAGCAGACGGCCC-3′ Repeat 2: Forward primer: (SEQ ID NO: 21) 5′-GGggtaccTCTCTGGTACTCTTCGATC-3′ Reverse primer: (SEQ ID NO: 22) 5′-TCCcccgggCGACCAGCAGACGGCCC-3′ The underlined portions represent introduced restriction sites Sma I (cccggg) or Kpn I (ggtacc) for cloning.

The three fragments (hpt, repeat #1 and repeat #2) were amplified in separate reactions (50 μl each) composed of 1× ThermoPol reaction buffer, 200 μM dNTPs, 0.25 μM each primer, 50 ng of template DNA, and 1 unit of VENT® DNA polymerase. The amplification reaction was performed using a ROBOCYCLER® programmed for 1 cycle at 95° C. for 2 minutes; 30 cycles each at 95° C. for 1 minute, 61° C. for 1 minute, and 72° C. for 2 minutes; and 1 cycle at 72° C. for 7 minutes.

The PCR products were separated by 1.5% agarose gel electrophoresis in TAE buffer. The approximately 2 kb amplified hpt fragment and the approximately 0.2 kb repeat fragments were excised from the gels and extracted using a MINELUTE® Gel Extraction Kit (QIAGEN Inc., Valencia, Calif., USA). The two pyrG repeat fragments were digested with Kpn I, dephosphorylated with calf intestine phosphatase (New England Biolabs Inc., Ipswich, Mass., USA), and treated with a MINELUTE® Reaction Cleanup Kit (QIAGEN Inc., Valencia, Calif., USA) according to the manufacturer's instructions. The fragments harboring repeat #1 and hpt were then ligated together using a QUICK LIGATION™ Kit (New England Biolabs Inc., Ipswich, Mass., USA) according to the manufacturer's instructions, and treated with a MINELUTE® Reaction Cleanup Kit, and the resulting ligation cloned into pCR® II Blunt using a TOPO® Blunt Cloning Kit. Sequence analysis confirmed one clone in which repeat #1 and the hpt fragment were ligated together in pCR® II Blunt. This plasmid was designated pEmY18.

In order to clone the second repeat into pEmY18, pEmy18 was digested with Eco RV and the digestion purified by 1% agarose gel electrophoresis in TAE buffer. A 5.6 kb fragment was excised from the gel and extracted using a QIAQUICK® Gel Extraction Kit. The 0.2 kb Repeat 2 fragment (described above) and digested pEmY18 were ligated together using a QUICK LIGATION™ Kit. The ligation mixture was used to transform SOLOPACK® Gold Supercompetent Cells (Stratagene, La Jolla, Calif., USA). Sequence analysis identified a plasmid in which the three components (repeat #1, hpt and repeat #2) were in the desired order and orientation and lacked PCR errors. The resulting plasmid was designated pEmY20.

To insure that subsequent digestion of pEmY20 with Eco RI would liberate a single fragment, an Eco RI site was removed using a QUIKCHANGE® Site-Directed Mutagenesis Kit according to the manufacturer's instructions and forward and reverse primers shown below. The resulting plasmid was designated pEmY21 (FIG. 2) after sequence verification.

Forward primer: (SEQ ID NO: 23) 5′-GGGTACCCCAAGGGCQTATTCTGCAGATGGG-3′ Reverse primer: (SEQ ID NO: 24) 5′-CCCATCTGCAGAATACGCCCTTGGGGTACCC-3′

Example 3: Construction of Plasmid pEmY23

The Fusarium venenatum pyrG coding sequence (2,678 bp) was excised from pDM156.2 (Example 1) by digestion with Eco RV and Stu I restriction endonucleases, and the remaining 4,398 bp vector was gel-purified using a QIAQUICK® Gel Extraction Kit according to the manufacturer's directions. The Sma I fragment of pEmY21 was isolated and gel-purified using a QIAQUICK® Gel Extraction Kit and the two gel-purified fragments were ligated together. They were screened for insert orientation, sequenced for the absence of errors, and one of the clones with the correct insert sequence was selected and designated pEmY23 (FIG. 3).

Example 4: Construction of Plasmid pWTY1470-19-07

Plasmid pJRoy40 (U.S. Pat. No. 7,332,341), which harbors 5′ and 3′ flanking sequences of a Fusarium venenatum trichodiene synthase (tri5) gene (SEQ ID NO: 25 for the DNA sequence and SEQ ID NO: 26 for the deduced amino acid sequence), was used as template for amplification of a portion of the 5′ tri5 gene flanking sequence. The PCR reaction contained 200 μM dNTPs, 1×Taq DNA polymerase buffer, 125 μg of pJRoy40 DNA, 50 pmol of each primer shown below, and 1 unit of Taq DNA polymerase in a final volume of 50 μl.

Forward primer: (SEQ ID NO: 27) 5′-GGGAGATCTTCGTTATCTGTGCC-3′ Reverse primer: (SEQ ID NO: 28) 5′-GGGAGATCTTAGTAGTCGGCATTTGAAAC-3′ (Underlined nucleotides indicate introduced BgI II sites).

The amplification reaction was incubated in a ROBOCYCLER® programmed for 1 cycle at 95° C. for 3 minutes; 10 cycles each at 95° C. for 30 seconds, 52° C. for 45 seconds, and 7° C. for 2 minutes; 20 cycles each at 95° C. for 30 seconds, 52° C. for 45 seconds, and 72° C. for 5 minutes; and 1 cycle at 72° C. for 7 minutes.

PCR products were separated by 1.5% agarose gel electrophoresis using TBE buffer. A fragment of approximately 600 bp was excised from the gel and extracted using a MINELUTE® Gel Extraction Kit. The fragment was inserted into pCR®2.1 (Invitrogen, Carlsbad, Calif., USA) using a TOPO® TA Cloning Kit (Invitrogen, Carlsbad, Calif., USA) and ONE SHOT® TOP10 competent cells were transformed with 2 μl of the TOPO® TA cloning reaction. Plasmid DNA from eight of the resulting transformants was digested with Eco RI and Bgl II in separate reactions and the inserts for three transformants with the correct restriction digestion patterns were confirmed by DNA sequencing. One clone with the desired sequence was selected and designated pWTY1470-09-05.

A 608 bp Bgl II fragment harboring the tri5 gene 5′ repeat was liberated from pWTY1470-09-05 by digestion with Bgl II, purified by 1.0% agarose gel electrophoresis using TBE buffer, excised from the gel, and extracted using a MINELUTE® Gel Extraction Kit.

Plasmid pJRoy40 was linearized by digestion with Bgl II, after which it was dephosphorylated using shrimp alkaline phosphatase (Roche Diagnostics Corporation, Indianapolis, Ind., USA) according to the manufacturer's instructions, and purified using a QIAQUICK® PCR Purification Kit (QIAGEN Inc., Valencia, Calif., USA). Linearized pJRoy40 and the gel-purified Bgl II fragment were ligated together using T4 DNA ligase (New England Biolabs Inc., Ipswich, Mass., USA) according to the manufacturer's instructions. Transformation of E. coli SURE® chemically competent cells (Stratagene, La Jolla, Calif., USA) was performed according to the manufacturer's directions. One transformant was confirmed by DNA sequencing to contain the desired vector, i.e., harboring the tri5 5′ and 3′ flanking sequences and a repeat of a portion of the 5′ flanking sequence. The resulting plasmid was designated pWTY1470-19-07 (FIG. 4).

Example 5: Construction of Plasmid pWTY1515-02-01

Plasmid pWTY1470-19-07 was subjected to in vitro mutagenesis using a QUIKCHANGE® Site-Directed Mutagenesis Kit according to the manufacturer's instructions and forward and reverse primers shown below.

Forward primer: (SEQ ID NO: 29) 5′-CAAGTAACAGACGCGACAGCTTGCAAAATCTTCGTTATCTGTG-3′ Reverse primer: (SEQ ID NO: 30) 5′-CACAGATAACGAAGATTTTGCAAGCTGTCGCGTCTGTTACTTG-3′

The mutagenesis removed the Bgl II site at 1779 bp and rendered the Bgl II site at 2386 bp unique and usable in subsequent manipulations to insert fragments harboring thymidine kinase (tk) and hygromycin phosphotransferase (hpt) gene cassettes. The mutagenesis reaction was used to transform the kit-supplied E. coli XL10-GOLD® Ultra-competent cells (Stratagene, La Jolla, Calif., USA) according to the manufacturer's suggested protocol.

One transformant harboring the mutations indicated above, as verified by sequence analysis, was designated pWTY1515-2-01 (FIG. 5) and used as the backbone in Example 8.

Example 6: Construction of Plasmid pJaL574

Plasmid pDV8 (U.S. Pat. No. 6,806,062) harbors the Herpes simplex virus type 1 thymidine kinase (HSV1-TK; tk) gene (SEQ ID NO: 31 for the DNA sequence and SEQ ID NO: 32 for the deduced amino acid sequence) as a 1.2 kb Bgl II/Bam HI fragment inserted between a 1.0 kb Xho I/Bgl II fragment of the Aspergillus nidulans glyceraldehyde-3-phosphate dehydrogenase (gpdA) promoter and a 1.8 kb Bam HI/Hind III fragment harboring the tri-functional Aspergillus nidulans indoleglycerolphosphate synthase, phosphoribosylanthranilate isomerase, and glutamine amidotransferase (trpC) transcriptional terminator. Plasmid pDV8 was digested with Bam HI, extracted with phenol-chloroform, ethanol precipitated, and then filled in using Klenow polymerase (Stratagene, La Jolla, Calif., USA). The digested plasmid was re-ligated using a QUICK LIGATION™ Kit following the manufacturer's protocol, treated with a MINELUTE® Gel Extraction Kit, and the resulting ligation products cloned into pCR®4Blunt-TOPO® (Invitrogen, Carlsbad, Calif., USA) using a TOPO® Blunt Cloning Kit according to the manufacturer's instructions. The cloning reaction was transformed into ONE SHOT® chemically competent TOP10 cells according to the manufacturer's directions. Plasmid DNA was extracted from eight of the resulting transformants using a BIOROBOT® 9600 (QIAGEN Inc, Valencia, Calif., USA) and screened by restriction digestion using Xho I/Bam HI and Xho I/Hind III. DNA sequencing of plasmid DNA from two transformants with the correct restriction digestion pattern confirmed that both harbored the desired sequence. One was named pJaL504-[Bam HI] (FIG. 6).

Plasmid pJaL504-[Bam HI] was digested with Bgl II, extracted with phenol-chloroform, ethanol precipitated, and then filled in using Klenow polymerase. The digested plasmid was re-ligated using a QUICK LIGATION™ Kit following the manufacturer's protocol, treated with a MINELUTE® Reaction Cleanup Kit, and the resulting ligation cloned into pCR®4Blunt-TOPO® using a TOPO® Blunt Cloning Kit according to the manufacturer's instructions. The cloning reaction was transformed into ONE SHOT® chemically competent E. coli TOP10 cells according to the manufacturer's directions. Plasmid DNA was extracted from eight of the resulting transformants using a BIOROBOT® 9600 and screened by restriction digestion using Xho I/Bgl II and Xho I/Hind III. DNA sequencing of plasmid DNA from two transformants with the correct restriction digestion pattern confirmed that both harbored the desired sequence. One was named pJaL504-[Bgl II] (FIG. 7). Punt et al. (1990, Gene 3: 101-109) have previously shown that 364 bp of the Aspergillus nidulans gpdA promoter could be deleted without affecting the strength of the promoter. Based on these authors' observations, primer #172450 shown below was designed to truncate the Aspergillus nidulans gpdA promoter and reduce the size of the vector.

Primer 172450: (SEQ ID NO: 33) 5′-GACGAATTCTCTAGAAGATCTCTCGAGGAGCTCAAGCTTCTGTACAG TGACCGGTGACTC-3′ The underlined sequence corresponds to gpdA promoter sequence. The remaining sequence is a handle harboring the following restriction sites: Eco RI, Xba I, Bgl II, Xho I, and Hind III.

For truncating the Aspergillus nidulans trpC terminator (again to reduce vector size), primer #172499, shown below, was designed harboring an Eco RI handle.

Primer 172499: (SEQ ID NO: 34) 5′-GACGAATTCCGATGAATGTGTGTCCTG-3′

The underlined sequence corresponds to the trpC terminator sequence. Amplification using primers 172499 and 172450 truncates the promoter by 364 bp and the trpC terminator sequence by 239 bp.

PCR was performed with the above two primers using pJaL504-[Bgl II] as template to generate a 2,522 bp fragment composed of a truncated version of the A. nidulans gpdA promoter, the coding sequence of the HSV1-TK gene, and a truncated version of the A. nidulans trpC terminator.

The amplification reaction consisted of 5 μl of 10× Buffer (Promega Corporation, Madison, Wis., USA), 0.4 μl of 25 mM dNTPs, 1.25 μl of primer 172450 (100 ng/μl), 1.25 μl of primer 172499 (100 ng/μl), 0.5 μl of pJaL504-[Bgl II] (100 ng/μl), 2 μl of Pfu DNA polymerase (Promega Corporation, Madison, Wis., USA) (2.5 U/μl), and 39.6 μl of sterile distilled water. The amplification reaction was incubated in a ROBOCYCLER® programmed for 1 cycle at 95° C. for 45 seconds; and 28 cycles each at 95° C. for 45 seconds, 57° C. for 45 seconds, and 72° C. for 5 minutes. A final extension was performed for 10 minutes at 72° C.

The amplification reaction was subjected to 1% agarose gel electrophoresis using low melting temperature agarose in 50 mM Tris-50 mM boric acid-1 mM disodium EDTA (TBE) buffer. A 2,522 bp fragment was excised from the gel and extracted using a QIAQUICK® Gel Extraction Kit. The gel-purified DNA was then inserted into pCR®4Blunt-TOPO® using a TOPO® Blunt Cloning Kit according to the manufacturer's instructions. The cloning reaction was transformed into ONE SHOT® chemically competent TOP10 cells according to the manufacturer's directions. Plasmid DNA was extracted from eight of the resulting transformants using a BIOROBOT® 9600 and screened by restriction digestion using Eco RI and Bgl II. DNA sequencing of plasmid DNA from two transformants with the correct restriction digestion pattern confirmed that both harbored the desired sequence. One was designated pJaL574 (FIG. 8).

Example 7: Construction of Plasmid pWTY1449-02-01

Plasmid pJaL574 was transformed into competent E. coli SCS110 cells (Stratagene, La Jolla, Calif., USA) following the manufacturer's recommended protocol. Plasmid DNA was extracted from twenty-four of the resulting transformants using a BIOROBOT® 9600, and then subjected to analytical digestion using Eco RI and Bgl II. Subsequent DNA sequence analysis resulted in the identification of a clone with the correct sequence, which was designated pWTY1449-02-01 (FIG. 9).

Example 8: Generation of the Tri5 Deletion Vector pJfyS1579-21-16

An E. coli hygromycin phosphotransferase (hpt) gene cassette was PCR amplified from plasmid pEmY23 using an ADVANTAGE® GC Genomic PCR Kit (Clontech, Palo Alto, Calif., USA) and gene-specific forward and reverse primers shown below. The underlined portion in the reverse primer is a Bgl II site for cloning.

Forward primer: (SEQ ID NO: 35) 5′-TTGAACTCTCAGATCCCTTCATTTAAACGGCTTCACGGGC-3′ Reverse primer: (SEQ ID NO: 36) 5′-CAGATAACGAAGATCTACGCCCTTGGGGTACCCAATATTC-3′

The amplification reaction contained 362 ng of pEmY23 as DNA template, 200 μm dNTP's, 1.1 mM magnesium acetate, 0.4 μM primers, 1×GC Reaction Buffer (Clontech, Palo Alto, Calif., USA), 0.5 M GC Melt (Clontech, Palo Alto, Calif., USA), and 1×GC Genomic Polymerase Mix (Clontech, Palo Alto, Calif., USA) in a final volume of 50 μl. The amplification reaction was incubated in an EPPENDORF® MASTERCYCLER® (Eppendorf, Munich, Germany) programmed for 1 cycle at 95° C. for 2 minutes; 25 cycles each at 94° C. for 30 seconds and 66° C. for 3 minutes; and 1 cycle at 66° C. for 3 minutes; and hold at 4° C.

PCR products were separated by 1% agarose gel electrophoresis using TAE buffer. A fragment of approximately 1.9 kb was excised from the gel and extracted using a MINIELUTE® Gel Extraction Kit. The fragment was cloned into pCR®2.1 using a TOPO® TA Cloning Kit according to the manufacturer's instructions. ONE SHOT® TOP10 competent cells were transformed with 2 μl of the TOPO® TA reaction. Sequence analysis of plasmid DNA from 8 transformants confirmed that there were no deviations from the expected sequence and the plasmid was designated pJfyS1540-75-5 (FIG. 10).

The hpt insert was liberated from pJfyS1540-75-5 by digestion with Bam HI and Bgl II and purified by 1% agarose gel electrophoresis in TAE buffer. A fragment of 1.9 kb was excised and extracted using a MINIELUTE® Gel Extraction Kit. A Rapid DNA Ligation Kit was used to ligate the fragment to Bgl II-linearized empty tri5 deletion vector pWTY1515-2-01 (Example 5) which had been dephosphorylated using calf intestine phosphatase. E. coli SURE® chemically competent cells were transformed with the ligation reaction and plasmid DNA from 24 of the resulting transformants was analyzed by restriction digestion with Eco RI to confirm the orientation of the insert. One of the transformants harboring the insert in the desired orientation was selected and designated pJfyS1579-1-13 (FIG. 11).

A Herpes simplex virus thymidine kinase (tk) gene (SEQ ID NO: 31 for the DNA sequence and SEQ ID NO: 32 for the deduced amino acid sequence) was PCR amplified using pWTY1449-02-01 as template and gene specific forward and reverse primers shown below. The bold sequence represents the introduced Bgl II site.

Forward primer: (SEQ ID NO: 37) 5′-GCCGACTACTAGATCGACCGGTGACTCTTTCTGGCATGCG-3′ Reverse primer: (SEQ ID NO: 38) 5′-CAGATAACGAAGATCTGAGAGTTCAAGGAAGAAACAGTGC-3′

The amplification reaction contained 1× HERCULASE® reaction buffer (Stratagene, La Jolla, Calif., USA), 200 μM dNTPs, 55 ng of pWTY1449-02-01, 0.2 μM primers, 2% DMSO, and 2.5 units of HERCULASE® DNA polymerase (Stratagene, La Jolla, Calif., USA) in a final volume of 50 μl. The amplification reaction was incubated in an EPPENDORF® MASTERCYCLER® programmed for 1 cycle at 95° C. for 1 minute; 25 cycles each at 94° C. for 30 seconds, 60° C. for 30 seconds, and 68° C. for 2 minutes and 45 seconds; and 1 cycle at 68° C. for 2 minutes and 45 seconds; and a hold at 4° C.

PCR products were separated by 1% agarose gel electrophoresis using TAE buffer. A fragment of approximately 2.8 kb was excised from the gel and purified using a MINIELUTE® Gel Extraction Kit. The fragment was cloned into pCR®2.1 using a TOPO® TA Cloning Kit. ONE SHOT® TOP10 competent cells were transformed with 2 μl of the TOPO® TA reaction. Sequence analysis of plasmid DNA from one of the transformants identified a mutation in the tk coding sequence (C1621G) resulting in an amino acid change of glycine to alanine. This mutation was corrected using a QUIKCHANGE® II XL Site-Directed Mutagenesis Kit (Stratagene, La Jolla, Calif., USA) according to the manufacturer's instructions and forward and reverse primers shown below. The lower case letter indicates the desired change. Sequence analysis of 16 clones resulted in the selection of one which was designated pJfyS1579-8-6 (FIG. 12).

Forward primer: (SEQ ID NO: 39) 5′-CCCTGTTTCGGGgCCCCGAGTTGCTGG-3′ Reverse primer: (SEQ ID NO: 40) 5′-CCAGCAACTCGGGGcCCCGAAACAGGG-3′

Plasmid pJfyS1579-8-6 was digested with Bam HI and Bgl II to liberate the 2.8 kb tk fragment and the fragment was purified as described above. This fragment was ligated to pJfyS1579-1-13, which had been linearized with Bgl II and treated with calf intestine phosphatase, using a QUICK LIGATION™ Kit and used to transform E. coli SURE® chemically competent cells according to the manufacturer's protocol. The resulting plasmid was designated pJfyS1579-21-16 (FIG. 13) and used as the tri5 deletion cassette.

Example 9: Construction of a Universal Deletion Vector Harboring the Thymidine Kinase (tk) Negative Selection Marker and Hygromycin Phosphotransferase (Hpt) Positive Selection Marker

A universal deletion vector harboring both the thymidine kinase (tk) and hygromycin phosphotransferase (hpt) markers was constructed to facilitate assembly of subsequent deletion plasmids. Flanking sequences for 5′ and 3′ regions of the gene targeted for deletion can be easily ligated to the vector following digestion of the latter with Pme I or Asc I (for 5′ flanking sequences) and Sbf I or Swa I (for 3′ flanking sequences).

In order to PCR amplify the direct repeats derived from the 5′ flanking region of the Fusarium venenatum pyrG gene, 50 picomoles of the primers shown below were used in two PCR reactions containing 50 ng of pDM156.2, 1×Pfx Amplification Buffer (Invitrogen, Carlsbad, Calif., USA), 6 μl of a 10 mM blend of dNTPs, 2.5 units of PLATINUM® Pfx DNA polymerase (Invitrogen, Carlsbad, Calif., USA), and 1 μl of 50 mM MgSO₄ in a total volume of 50 μl.

Primers:

Repeat #1 Sense Primer: (SEQ ID NO: 41) 5′-GTTTAAACGGCGCGCC CGACAAAACAAGGCTACTGCAGGCAGG-3′ Antisense Primer: (SEQ ID NO: 42) 5′-TTGTCGCCCGGG AATACTCCAACTAGGCCTTG-3′ Repeat #2 Sense Primer: (SEQ ID NO: 43) 5′-AGTATTCCCGGG CGACAAAACAAGGCTACTGCA-3′ Antisense Primer: (SEQ ID NO: 44) 5′-ATTTAAATCCTGCAGG AATACTCCAACTAGGCCTTG-3′

The amplification reactions were incubated in an EPPENDORF® MASTERCYCLER® programmed as follows. For repeat #1: 1 cycle at 98° C. for 2 minutes; and 5 cycles each at 94° C. for 30 seconds, 55° C. for 30 seconds, and 68° C. for 1 minute. This was followed by 35 cycles each at 94° C. for 30 seconds, 59° C. for 30 seconds, and 68° C. for 1 minute. For repeat #2 the cycling parameters were: 1 cycle at 98° C. for 2 minutes; and 5 cycles each at 94° C. for 30 seconds, 55° C. for 30 seconds, and 68° C. for 1 minute. This was followed by 35 cycles each at 94° C. for 30 seconds, 56° C. for 30 seconds, and 68° C. for 1 minute. After the 35 cycles both reactions (i.e., repeats #1 and #2) were incubated at 68° C. for 10 minutes and then cooled at 10° C. until being further processed.

PCR products from both reactions were separated by 0.8% GTG-agarose (Cambrex Bioproducts, East Rutherford, N.J., USA) gel electrophoresis using TAE buffer. For repeat #1 and repeat #2, fragments of approximately 0.26 kb were excised from the gels and purified using Ultrafree®-DA spin cups (Millipore, Billerica, Mass., USA) according to the manufacturer's instructions. Ten microliters of each purified repeat were then used in a single overlapping PCR reaction containing 1×Pfx Amplification Buffer, 6 μl of a 10 mM blend of dATP, dTTP, dGTP, and dCTP, 2.5 units of PLATINUM® Pfx DNA polymerase, and 1 μl of 50 mM MgSO₄ in a total volume of 50 μl. The amplification reaction was incubated in an EPPENDORF® MASTERCYCLER® programmed for 1 cycle at 98° C. for 2 minutes; and 5 cycles each at 94° C. for 30 seconds, 50° C. for 30 seconds, and 68° C. for 1 minute. The reaction was then mixed with a pre-warmed solution containing 50 picomoles of the sense primer for repeat #1 and 50 picomoles of the anti-sense primer for repeat #2, 1×Pfx Amplification Buffer, 6 μl of a 10 mM dNTPs, 2.5 units of PLATINUM® Pfx DNA polymerase, and 1 μl of 50 mM MgSO₄ in a final volume of 50 μl.

The new 100 μl amplification reaction was incubated in an EPPENDORF® MASTERCYCLER® programmed for 35 cycles each at 94° C. for 30 seconds, 58° C. for 30 seconds, and 68° C. for 1 minute. After 35 cycles, the reaction was incubated at 68° C. for 10 minutes and then cooled at 10° C. until being further processed. A 0.5 kb PCR product (harboring the repeat assembly) was isolated by 0.8% GTG-agarose gel electrophoresis as described above.

Plasmid pCR4 (Invitrogen, Carlsbad, Calif., USA) was used as the source of the vector backbone for the construction of the universal deletion vector. To remove the non-essential portions of the pCR4 DNA, 2.5 μg of plasmid pTter61C (WO 2005/074647) were digested sequentially with Bsp LU11 I and Bst XI. The digested vector was then treated with Antarctic phosphatase (New England Biolabs Inc., Ipswich, Mass., USA). The 3.1 kb digested backbone was isolated by 0.8% GTG-agarose gel electrophoresis as described above. The purified repeat assembly was then ligated to the purified vector backbone with a Rapid Ligation Kit (Roche Diagnostics Corporation, Indianapolis, Ind., USA). The ligation reaction consisted of: 75 ng of purified vector backbone and 3 μl of the purified repeat assembly. One microliter of this ligation reaction was used to transform chemically competent SOLOPACK® Supercompetent cells (Stratagene, Carlsbad, Calif., USA) using the manufacturer's protocol. Twenty-four transformants were analyzed by Nco I/Pme I restriction digestion. Twenty-three out of twenty four transformants had the expected restriction digestion pattern. Clone pFvRs #10 was selected at random for sequencing to confirm that there were no PCR-induced errors. Sequencing analysis showed that the repeat assembly in clone pFvRs #10 had the expected sequence, and was designated pAlLo1492-24 (FIG. 14).

The cassette harboring the hygromycin phosphotransferase (hpt) gene was PCR amplified from pEmY23 using the gene-specific forward and reverse primers shown below. The underlined sequence represents a Xma I site and the bold letters represent a Bgl II site. The four “a”s at each 5′ end allow for subsequent digestion of the terminal ends of the PCR product.

Forward primer: (SEQ ID NO: 45) 5′-aaaacccgggCCTTCATTTAAACGGCTTCACGGGC-3′ Reverse primer: (SEQ ID NO: 46) 5′-aaaacccggg AGATCTACGCCCTTGGGGTACCCAATATTC-3′

The amplification reaction contained 60 ng of pEmY23, 200 μm dNTPs, 1 mM magnesium acetate, 0.4 μM primers, 1×Pfx Amplification Buffer, 0.5 M GC Melt, and 2.5 units of PLATINUM® Pfx DNA polymerase in a final volume of 50 μl. The reaction was incubated in an EPPENDORF® MASTERCYCLER® programmed for 1 cycle at 95° C. for 2 minutes; 10 cycles each at 94° C. for 30 seconds, 60° C. for 30 seconds, and 68° C. for 1 minute 50 seconds; and 1 cycle at 68° C. for 7 minutes followed by holding at 4° C.

PCR products were separated by 1% agarose gel electrophoresis using TAE buffer. A fragment of approximately 1.8 kb was excised from the gel and extracted using a MINIELUTE® Gel Extraction Kit. The gel-purified PCR product was subsequently digested with Xma I and run on a 1% agarose gel and gel-purified again as above. A QUICK LIGATION™ Kit was used to ligate the hpt PCR product to Xma I-linearized pAlLo1492-24, which had been treated with calf intestine phosphatase. The resulting plasmid was designated pJfyS1579-35-2 (FIG. 15) and was used as the recipient for the insertion of the thymidine kinase gene.

The source of the Herpes simplex virus tk cassette was plasmid pJfyS1579-8-6 (Example 8), from which the insert was liberated by digestion with Bam HI and Bgl II. The digestion products were separated by 1% agarose gel electrophoresis using TAE buffer, and a fragment corresponding to the 2.8 kb tk gene insert was excised and extracted using a MINELUTE® Gel Extraction Kit. A QUICK LIGATION™ Kit was used to ligate the tk gene cassette to Bgl II-linearized pJfyS1579-35-2, which had been treated with calf intestine phosphatase. The resulting plasmid was designated pJfyS1579-41-11 (FIG. 16).

Example 10: Trichoderma reesei Strain 981-O-8 Genomic DNA Extraction

Trichoderma reesei strain 981-O-8 was grown in 50 ml of YEG medium in a baffled shake flask at 28° C. for 2 days with agitation at 200 rpm. Mycelia were harvested by filtration using MIRACLOTH® (Calbiochem, La Jolla, Calif., USA), washed twice in deionized water, and frozen under liquid nitrogen. Frozen mycelia were ground, by mortar and pestle, to a fine powder, and total DNA was isolated using a DNEASY® Plant Maxi Kit (QIAGEN Inc., Valencia, Calif., USA).

Example 11: Construction of Trichoderma reesei Subtilisin-Like Serine Protease Gene Deletion Plasmid pDAtw18

To construct a Trichoderma reesei subtilisin-like serine protease gene deletion cassette, a 1.4 kb fragment of the downstream non-coding region of the Trichoderma reesei subtilisin-like serine protease gene (SEQ ID NO: 1 for the DNA sequence and SEQ ID NO: 2 for the deduced amino acid sequence) was PCR amplified using oligonucleotides 067375 and 067376 shown below.

Primer 067375: (SEQ ID NO: 47) 5′-AAAAAACCTGCAGGGATGTAAGAGGGTTTCTTGAGGGGT-3′ Primer 067376: (SEQ ID NO: 48) 5′-AAAAAACCTGCAGG GCGGCCG CTGATAGTAGACATGATACTG-3′ Underlined letters represent a Sbf I site added to the sense and antisense primers to facilitate cloning of the amplified fragment and the bold region represents a Not I site introduced for later restriction digestion to remove a β-lactamase gene for fungal transformation.

The amplification reaction was composed of 300 ng of the Trichoderma reesei strain 981-O-8 genomic DNA (Example 10), 300 μM dNTPs, 50 pmol of primer 067375, 50 pmol of primer 067376, 1× reaction buffer, 1 mM MgSO₄ and 2.5 units of PLATINUM® Pfx DNA polymerase (Invitrogen Corp., Carlsbad, Calif., USA). The reaction was incubated in an EPPENDORF® MASTERCYCLER® 5333 (Eppendorf Scientific, Inc., Westbury, N.Y., USA) programmed for 1 cycle at 98° C. for 5 minutes; 30 cycles each at 98° C. for 30 seconds, 58° C. for 30 seconds, and 72° C. for 1.6 minutes; and 1 cycle at 72° C. for 15 minutes. A 1442 bp PCR fragment was isolated by 1% agarose gel electrophoresis using TAE buffer, excised from the gel, and extracted using a MINELUTE® Gel Extraction Kit. The 1442 bp PCR product was cloned into pCR®2.1 TOPO® (Invitrogen Corp., Carlsbad, Calif., USA) and transformed into Chemically Competent E. coli cells according to the manufacturer's instructions. Transformants were selected on 2×YT agar plates supplemented with 100 μg of ampicillin per ml and incubated at 37° C. for 16 hours. The DNA sequence of the cloned fragment was verified by DNA sequencing with M13 forward and reverse primers. The resulting plasmid was designated pClone10.

Similarly, a 1.5 kb fragment of the upstream non-coding region of the Trichoderma reesei subtilisin-like serine protease gene (SEQ ID NO: 1 for the DNA sequence and SEQ ID NO: 2 for the deduced amino acid sequence) was PCR amplified using primers 067377 and 067374 shown below.

Primer 067377: (SEQ ID NO: 40) 5′-AAAAAAGGCGCGCC GCGGCCGCAATGGATAGCTAATAATCAA-3′ Primer 067374: (SEQ ID NO: 50) 5′-AAAAAAGGCGCGCCACTGTGGGAGGGCTGTATGGACA-3′ Underlined letters represent an Asc I site added to the sense and antisense primers to facilitate the cloning of the amplified fragment and the bold region represents a Not I site

The PCR amplification was performed under the same conditions described above except primers 067377 and 067374 were used. A 1530 bp PCR fragment was isolated by 1% agarose gel electrophoresis using TAE buffer, excised from the gel, and extracted using a MINELUTE® Gel Extraction Kit. The 1530 bp amplified fragment was cloned into pCR®2.1 TOPO® vector and transformed into Chemically Competent E. coli cells according to the manufacturer's instructions. Transformants were selected on 2×YT agar plates supplemented with 100 μg of ampicillin per ml and incubated at 37° C. for 16 hours. The DNA sequence of the cloned fragment was verified by DNA sequencing with M13 forward and reverse primers. The resulting plasmid was designated pClone1.

Plasmid pClone1 was digested with Asc I and the digestion purified by 1% agarose gel electrophoresis in TAE buffer. A 1415 bp fragment containing the upstream non-coding region of the Trichoderma reesei subtilisin-like serine protease gene fragment was excised from the gel and extracted using a MINELUTE® Gel Extraction Kit. This insert was ligated to Asc I digested and calf intestinal phosphatase (CIP) dephosphorylated pJfyS1579-41-11 (Example 9) using a QUICK LIGATION™ Kit (New England Biolabs, Beverly, Mass., USA) according to the manufacturer's suggested protocol. Restriction analysis was used to identify transformants containing the insert in the desired orientation and sequence analysis was performed to confirm the absence of PCR errors. The resulting plasmid was designated pClone14.

The final Trichoderma reesei subtilisin-like serine protease gene deletion cassette, pDAtw18 (FIG. 17), was created by digesting pClone10 with Sbf I to release the 1.5 kb downstream non-coding region of the Trichoderma reesei subtilisin-like serine protease gene fragment, which was then ligated to Sbf I digested and calf intestinal phosphatase (CIP) dephosphorylated pClone14 using a QUICK LIGATION™ Kit according to the manufacturer's suggested protocol. A linear 7.7 kb fragment containing the TrSpΔ::hpt/tk allele could then be generated by digestion with Not I.

Example 12: Trichoderma reesei Protoplast Generation and Transformation

Protoplast preparation and transformation were performed using a modified protocol by Penttila et al., 1987, Gene 61: 155-164. Briefly, Trichoderma reesei strain 981-O-8 was cultivated in 25 ml of YP medium supplemented with 2% (w/v) glucose and 10 mM uridine at 27° C. for 17 hours with gentle agitation at 90 rpm. Mycelia were collected by filtration using a Millipore Vacuum Driven Disposable Filtration System (Millipore, Bedford, Mass., USA) and washed twice with deionized water and twice with 1.2 M sorbitol. Protoplasts were generated by suspending the washed mycelia in 20 ml of 1.2 M sorbitol containing 15 mg of GLUCANEX® 200 G (Novozymes A/S, Bagsvaerd, Denmark) per ml and 0.36 units of chitinase (Sigma Chemical Co., St. Louis, Mo., USA) per ml for 15-25 minutes at 34° C. with gentle shaking at 90 rpm. Protoplasts were collected by centrifuging for 7 minutes at 400×g and washed twice with cold 1.2 M sorbitol. The protoplasts were counted using a haemacytometer and re-suspended to a final concentration of 1×10⁸ protoplasts/ml in STC. Excess protoplasts were stored in a Cryo 1° C. Freezing Container (Nalgene, Rochester, N.Y., USA) at −80° C.

Approximately 10 μg of each of the deletion cassettes described in the following examples were digested with either Not I (Examples 13 and 20) or Hind III/Bgl II (Example 17). Each digestion reaction was purified by 1% agarose gel electrophoresis in TAE buffer, a DNA band was excised from the gel, and extracted using a QIAQUICK® Gel Extraction Kit. The resulting purified DNA was added to 100 μl of the protoplast solution and mixed gently. PEG buffer (250 μl) was added, mixed, and incubated at 34° C. for 30 minutes. STC (3 ml) was then added, mixed, and plated onto PDA medium supplemented with 1 M sucrose. After incubation at 28° C. for 16 hours, 15 ml of an overlay PDA medium supplemented with 100 μg of hygromycin B per ml was added to each plate. The plates were incubated at 28° C. for 4-6 days.

Example 13: Generation of Subtilisin-Like Serine Protease Gene Deletion Trichoderma reesei Strain DAtw18-97

Trichoderma reesei strain 981-O-8 protoplasts were transformed with Not I-linearized pDAtw18 using the method described in Example 12 to delete the subtilisin-like serine protease gene. One hundred and sixty-six transformants were selected on PDA plates containing 25 μg of hygromycin B per ml. The transformants were sub-cultured to PDA plates to generate spores. Each transformant was cultured in a 125 ml baffled shake flask containing 25 ml of cellulase-inducing medium at pH 6.0 and incubated at 28° C. for 7 days with agitation at 200 rpm. Trichoderma reesei strain 981-O-8 was run as a control. Culture broth samples were removed 7 days post-inoculation, centrifuged at 15,700×g for 5 minutes in a micro-centrifuge, and the supernatants transferred to new tubes.

A protease assay using a synthetic substrate, N-Succinyl-L-Ala-L-Ala-L-Pro-L-Phe-p-nitroanilide (AAPF) (Bachem AG, Bubendorf, Switzerland), was performed on the supernatants above to determine whether any of the transformants were deleted for the subtilisin-like serine protease gene. The substrate was initially dissolved in dimethyl sulfoxide at a concentration of 100 mg/ml. The dissolved substrate was then diluted 50-fold into 100 mM NaCl-100 mM MOPS pH 7.0. The reaction was initiated by adding 10 μl of each transformant supernatant to 100 μl of the diluted substrate in a flat-bottomed 96-well plate (Corning Inc., Acton, Mass., USA). The reaction plate was incubated at 50° C. for 3 hours and then the absorbance at 405 nm was measured using a SPECTRAMAX® Microplate Reader (Molecular Devices, Sunnyvale, Calif., USA). Protease activities of the Trichoderma reesei DAtw18 transformants were compared to that of parent strain Trichoderma reesei strain 981-O-8.

Fifteen transformants displaying lower extracellular protease activities compared to Trichoderma reesei strain 981-O-8 were then analyzed by Southern analysis. Genomic DNA from each of the 15 transformants was extracted as described in Example 11 and 2 μg of each were digested with 20 units of Nco I-HF™ (New England Biolabs, Inc., Ipswich, Mass., USA) for 16 hours at 37° C. Digested DNA was fractionated by 0.7% agarose gel electrophoresis using TAE buffer for 4 hours and blotted onto a NYTRAN™ SuperCharge membrane (Schleicher & Schuell BioScience, Keene, N.H., USA) using a TURBOBLOTTER™ (Schleicher & Schuell BioScience, Keene, N.H., USA) for 16 hours following the manufacturer's recommendations. The membrane was hybridized with a 502 bp digoxigenin-labeled subtilisin-like serine protease gene probe, which was synthesized by incorporation of digoxigenin-11-dUTP by PCR using primers 067911 (sense) and 067912 (antisense) shown below.

Primer 067911 (sense): (SEQ ID NO: 51) GCGGTCATTTACAGTGCCTCGAATA Primer 996117 (antisense): (SEQ ID NO: 52) CTGCTCTGTTAGCAATCCTCAAGCA

The amplification reaction (50 μl) was composed of 1× ThermoPol Reaction Buffer, 5 μl of PCR DIG Labeling Mix, 10 ng of pDAtw18, 0.3 μM primer 067911, 0.3 μM primer 067912, and 2.5 units of Taq DNA polymerase. The reactions were incubated in an EPPENDORF® MASTERCYCLER® 5333 programmed for 30 cycles each at 95° C. for 30 seconds, 56° C. for 30 seconds, and 72° C. for 40 seconds (15 minute final extension). Five microliters of the PCR product was size-selected by 1.5% agarose gel electrophoresis using TAE buffer, stained with ethidium bromide, and visualized under a UV transilluminator. Incorporation of digoxigenin was indicated by increase in molecular mass.

Hybridization was performed in DIG Easy Hyb buffer (Roche Molecular Biochemicals, Indianapolis, Ind., USA) at 42° C. for 17 hours. The membrane was then washed under high stringency conditions in 2×SSC plus 0.1% SDS for 5 minutes at room temperature followed by two washes in 0.5×SSC plus 0.1% SDS for 15 minutes each at 65° C. The probe-target hybrids were detected by chemiluminescent assay (Roche Molecular Biochemicals, Indianapolis, Ind., USA) following the manufacturer's instructions. Southern analysis indicated that all 15 transformants contained a single integration of the deletion cassette at the subtilisin-like serine protease gene locus without any further integration of the deletion fragment at other loci. One strain designated Trichoderma reesei DAtw18-97 was chosen for subsequent transformations.

Example 14: Construction of Plasmid pSaMe-AaXYL

Plasmid pSaMe-AaXYL was constructed to comprise the Trichoderma reesei cellobiohydrolase I gene promoter and terminator and the Aspergillus aculeatus GH10 xylanase coding sequence.

Cloning of the Aspergillus aculeatus xylanase followed the overall expression cloning protocol as outlined in H. Dalbøge et al., 1994, Mol. Gen. Genet. 243: 253-260.

RNA was isolated from Aspergillus aculeatus CBS 101.43 mycelium. Poly(A)⁺ RNA was isolated from total RNA by chromatography on oligo(dT)-cellulose. Double-stranded cDNA was synthesized as described by Maniatis et al. (Molecular cloning: a laboratory manual. Cold Spring Harbor Laboratory Press, 1982). After synthesis the cDNA was treated with mung bean nuclease, blunt-ended with T4 DNA polymerase, and ligated to non-palindromic Bst XI adaptors (Invitrogen, Carlsbad, Calif., USA). The cDNA was size fractionated by 1% agarose gel electrophoresis using TAE buffer where fragments ranging from 600 bp to 4000 bp were used in the library construction. The DNA was ligated into Bst XI-digested pYES 2.0 between the GAL1 promoter and the iso-1-cytochrome c terminator and transformed into Escherichia coli MC1061 cells (Stratagene, La Jolla, Calif., USA. The library was plated onto LB plates and incubated overnight at 37° C. The colonies were scraped from the plates and resuspended in LB medium supplemented with 100 μg of ampicillin per ml. Plasmid DNA was isolated using a Plasmid Midi Kit (QIAGEN Inc., Valenicia, Calif., USA). The purified plasmid DNA was pooled.

The purified plasmid DNA mixture was transformed into Saccharomyces cerevisiae W3124 cells (MATa; ura 3-52; leu 2-3, 112; his 3-D200; pep 4-1137; prcl::HIS3; prbl::LEU2; cir+; van den Hazel et al., 1992, Eur. J. Biochem. 207: 277-283). Cultivation, transformation and media were as described by Guthrie et al., 1991, Meth. Enzymol. Vol 194, Academic Press. The transformed cells were plated onto synthetic complete agar containing 2% glucose for 3 days at 30° C. After 3 days the colonies were replica plated to SC medium (Sherman, 2002, Methods Enzymol. 350: 3-41) with 2% galactose and incubated for 4 days at 30° C. Xylanase expressing colonies were identified by 1% agarose overlay with 0.1% AZCL-Birch-Xylan at pH 4.5 (Dalbøge, 2006, FEMS Microbiology Reviews 21: 29-42). Colonies expressing xylanase activity were surrounded by a blue zone. Plasmid DNA, rescued from the positive colonies, contained a DNA insert of approximately 1.3 kb. Sequencing of the isolated gene fragment revealed a 1218 bp open reading frame encoding a polypeptide with a theoretical molecular weight of 43.0 kDa. The cDNA fragment was subcloned into the Aspergillus expression vector pHD464 (Dalbøge and Heldt-Hansen, 1994, Mol. Gen. Genet. 243, 253-260) digested with Bam HI and Xho I by cutting the clone with Bam HI and Xho I and isolating the 1.2 kb cDNA insert (Christgau et al., 1996, Biochem. J. 319: 705-712) to generate plasmid pA2X2.

The Aspergillus aculeatus GH10 xylanase coding sequence was PCR amplified using plasmid pA2x2 as template and primers 153505 and 153506 shown below using standard methods to yield an approximately 1.2 kb fragment. The 1.2 kb fragment was digested with Bam HI and Xho I (introduced in the PCR primers) and cloned into vector pCaHj527 (WO 2004/099228). The resulting plasmid was designated pMT2155 in which the cDNA was under transcriptional control of the neutral amylase II (NA2) promoter from A. niger and the AMG terminator from A. niger.

Primer 153505: (SEQ ID NO: 53) 5′-TCTTGGATCCACCATGGTCGGACTGCTTTCAATCACC-3′ Primer 153506: (SEQ ID NO: 54) 5′-TTAACTCGAGTCACAGACACTGCGAGTAATAGTC-3′

Two synthetic oligonucleotide primers shown below were designed to PCR amplify the Aspergillus aculeatus GH10 gene from plasmid pMT2155 and introduce flanking regions for insertion into expression vector pMJ09 (WO 2005/056772). Bold letters represent coding sequence and the remaining sequence is homologous to the insertion sites of pMJ09.

Forward Primer:

5′-cggactgcgcaccatggtcggactgctttcaat-3′ (SEQ ID NO: 55)

Reverse Primer:

5′-tcgccacggagcttatcacagacactgcgagtaat-3′ (SEQ ID NO: 56)

The amplification reaction was composed of 50 picomoles of each of the primers above, 50 ng of pMT2155, 1 μl of 10 mM blend of dATP, dTTP, dGTP, and dCTP, 5 μl of 10× ACCUTAQ™ DNA Polymerase Buffer (Sigma-Aldrich, St. Louis, Mo., USA), and 5 units of ACCUTAQ™ DNA Polymerase (Sigma-Aldrich, St. Louis, Mo., USA), in a final volume of 50 μl. An EPPENDORF® MASTERCYCLER® 5333 was used to amplify the DNA fragment programmed for 1 cycle at 95° C. for 3 minutes; and 30 cycles each at 94° C. for 45 seconds, 55° C. for 60 seconds, and 72° C. for 1 minute 30 seconds. After the 30 cycles, the reaction was incubated at 72° C. for 10 minutes and then cooled to 4° C. until further processing.

The reaction products were isolated by 1.0% agarose gel electrophoresis using TAE buffer where a 1.2 kb product band was excised from the gel and purified using a QIAQUICK® Gel Extraction Kit according to the manufacturer's instructions.

The fragment was then cloned into pMJ09 using an IN-FUSION™ Cloning Kit (Clontech, Inc., Palo Alto, Calif., USA). The vector was digested with Nco I and Pac I and purified by agarose gel electrophoresis as described above. The 1.2 kb gene fragment and the digested vector were ligated together in a reaction resulting in the expression plasmid pSaMe-AaXYL in which transcription of the Family GH10 gene was under the control of the T. reesei cbh1 promoter. The ligation reaction (50 μl) was composed of 1× IN-FUSION™ Buffer (Clontech, Inc., Palo Alto, Calif., USA), 1×BSA, 1 μl of IN-FUSION™ enzyme (diluted 1:10) (Clontech, Inc., Palo Alto, Calif., USA), 100 ng of pAlLo2 digested with Nco I and Pac I, and 100 ng of the Aspergillus aculeatus GH10 xylanase purified PCR product. The reaction was incubated at room temperature for 30 minutes. One μl of the reaction was used to transform E. coli XL10 SOLOPACK® Gold cells (Stratagene, La Jolla, Calif., USA) according to the manufacturer. An E. coli transformant containing pSaMe-AaXYL (FIG. 18) was detected by restriction enzyme digestion and plasmid DNA was prepared using a BIOROBOT® 9600. DNA sequencing of the Aspergillus aculeatus GH10 gene from pSaMe-AaXYL was performed using dye-terminator chemistry (Giesecke et al., 1992, Journal of Virology Methods 38: 47-60) and primer walking strategy.

Example 15: Aspergillus aculeatus GH10 Xylanase Expression in Subtilisin-Like Serine Protease Deficient Strain DAtw18-97

Protoplasts were generated from subtilisin-like serine protease deficient strain Trichoderma reesei DAtw18-97 according to the procedure described in Example 12 and transformed with Trichoderma reesei expression construct pSaMe-AaXYL (Example 14) containing the Aspergillus aculeatus GH10 xylanase coding sequence to determine the stability of A. aculeatus xylanase GH10 expressed by T. reesei DAtw18-97. Transformation was performed by adding approximately 3 μg of Pme I digested and gel-purified pSaMe-AaXYL to 100 μl of protoplast solution and mixing gently. PEG buffer (250 μl) was added, mixed, and incubated at 37° C. for 30 minutes. STC (3 ml) was then added, mixed, and plated onto COVE plates. The plates were incubated at 28° C. for 7-10 days. After a single round of spore purification on COVE2 plates, 20 transformants were grown in small-scale shake flasks containing 25 ml of cellulase-inducing medium for 5 days at 28° C., after which supernatant were collected by centrifugation at 15,700×g for 10 minutes in a micro-centrifuge.

Expression of the Aspergillus aculeatus GH10 xylanase was analyzed using 8-16% CRITERION™ Tris-HCl gels (Bio-Rad Laboratories, Hercules, Calif., USA) with a CRITERION™ Cell (Bio-Rad Laboratories, Hercules, Calif., USA). Five μl of day 5 samples were suspended in 2× concentration of Laemmli Sample Buffer (Bio-Rad Laboratories, Hercules, Calif., USA) and heated at 95° C. for 5 minutes in the presence of 5% β-mercaptoethanol. All samples were loaded onto the CRITERION™ Tris-HCl gels and subjected to electrophoresis in 1× Tris/Glycine/SDS running buffer (Bio-Rad Laboratories, Hercules, Calif., USA). The resulting gels were stained with BIO-SAFE™ Coomassie Stain (Bio-Rad Laboratories, Hercules, Calif., USA). SDS-PAGE profiles of the cultures showed the presence of predominately the full-length Aspergillus aculeatus GH10 xylanase protein but also a smaller fragment present in lower quantities. The results suggested that deletion of the subtilisin-like serine protease gene for the production of Aspergillus aculeatus GH10 xylanase did not completely prevent proteolysis of the protein.

Example 16: Construction of Trichoderma reesei Aspartic Protease Gene Deletion Plasmid pAgJg111

The deletion vector pAgJg111 was constructed to disrupt expression of a Trichoderma reesei 42 kDa aspartic protease (SEQ ID NO: 3 for the DNA sequence and SEQ ID NO: 4 for the deduced amino acid sequence) in Trichoderma reesei strain 981-O-8. Plasmid pAgJg110 was generated first by amplifying the aspartic protease coding region plus and minus 600 bp upstream and downstream of the coding region using primers 066694 (sense) and 066695 (antisense) shown below.

Primer 066694 (sense): (SEQ ID NO: 57) ACGAATGGTCAAAGGACTATGTATCAT Primer 066695 (antisense): (SEQ ID NO: 58) CACATACCCAGAGTCAGGCCCTGCG

The aspartic protease region was amplified by PCR in a reaction composed of 316 ng of Trichoderma reesei strain 981-O-8 genomic DNA (Example 10), 1 μl of Herculase II Fusion DNA Polymerase (Stratagene, LaJolla, Calif., USA), 50 pmol of primer 066694, 50 pmol of primer 066695, 5 μl of 10 mM dNTPs, 5 μl of 5× Herculase II reaction buffer (Stratagene, LaJolla, Calif., USA), and 35 μl of water. The reaction was incubated in an EPPENDORF® MASTERCYCLER® 5333 programmed for 1 cycle at 95° C. for 2 minutes; 30 cycles each at 95° C. for 20 seconds, 60° C. for 20 seconds, and 72° C. for 1 minute 30 seconds; 1 cycle at 72° C. for 3 minutes; and a 4° C. hold. A 2.5 kb PCR fragment was purified by 1% agarose gel electrophoresis using TAE buffer, excised from the gel, and extracted using a QIAQUICK® Gel Extraction Kit according to the manufacturer's instructions.

The gel purified PCR fragment was treated with Taq DNA polymerase to add 3′ A-overhangs to the fragment in a reaction composed of 5 μl of the purified PCR fragment, 1 μl of the 10× Thermopol Buffer (New England Biolabs, Inc, Ipswich, Mass., USA), 0.5 μl of 10 mM dNTPs, 0.5 μl of Taq DNA polymerase, and 3 μl of water. The reaction was incubated at 72° C. for 15 minutes. The aspartic protease gene fragment was cloned into pCR®2.1-TOPO® according to the manufacturer's instruction to generate pAgJg110. The cloning reaction was composed of 2 μl of the aspartic protease PCR fragment, 1 μl of Salt Solution (Invitrogen, Carlsbad, Calif., USA), 2 μl of water, and 1 μl of pCR®2.1-TOPO®.

To construct plasmid pAgJg111, pAgJg110 was digested with Bmg I and BstE II in a reaction composed of 5 μg of pAgJg110 DNA, 3 μl of Bmg I, 3 μl of BstE II, 10 μl 10×NEB Buffer 3 (New England Biolabs, Inc, Ipswich, Mass., USA), 1 μl 100×BSA, and 53 μl of water. The digestion of pAgJg110 was incubated at 37° C. for 1 hour, and then at 60° C. for 1 hour. The digested pAgJg110 was then blunt ended by adding 10 μl of 10 mM dNTPs, and 12.5 units of DNA Polymerase I, Large (Klenow) Fragment (New England Biolabs, Inc, Ipswich, Mass., USA). The reaction was incubated at 37° C. for 15 minutes. The digested blunt ended pAgJg110 was purified by 1% agarose gel electrophoresis using TAE buffer, excised from the gel, and extracted using a QIAQUICK® Gel Extraction Kit according to the manufacturer's instructions.

Plasmid pHT (Cummings et al., 1999, Current Genetics 36: 371-382) was digested with Hind III and Ava I in a reaction composed of 1.86 μg of pHT DNA, 3 μl of Hind III, 3 μl of Ava I, 10 μl of 10×NEB Buffer 2 (New England Biolabs, Inc, Ipswich, Mass., USA), and 51 μl of water at 37° C. for 2.5 hours and then blunt ended by adding 10 μl of 10 mM dNTPs and 12.5 μl units of DNA Polymerase I, Large (Klenow) Fragment and incubating at 37° C. for 15 minutes. The digested blunt ended pHT was purified by 1% agarose gel electrophoresis using TAE buffer and a 1.9 kb fragment was excised from the gel and extracted using a QIAQUICK® Gel Extraction Kit according to the manufacturer's instructions.

The resulting fragments from pAgJg110 and pHT were ligated together to form pAgJg111 (FIG. 19) using T4 DNA Ligase in reaction composed of 88 ng of pHT fragment, 106 ng of pAgJg110 fragment, 1.5 μl of 10×T4 DNA Ligase Buffer (New England Biolabs, Inc, Ipswich, Mass., USA), 1 μl of T4 DNA Ligase (New England Biolabs, Inc, Ipswich, Mass., USA), and 0.5 μl of water.

Example 17: Generation of Aspartic Protease Gene Deletion Trichoderma reesei Strain AgJg111-50

Trichoderma reesei strain 981-O-8 protoplasts were transformed with Hind III/Bgl I-linearized pAgJg111 using the method described in Example 12 to delete the aspartic protease gene. Ninety transformants were selected on PDA plates containing 25 μg of hygromycin B per ml. The transformants were sub-cultured to PDA plates to generate spores.

Possible candidates of Trichoderma reesei strain 981-O-8 containing the pAgJg111 deletion vector in the aspartic protease locus, thereby disrupting the expression of the aspartic protease, were screened by Fungal Colony PCR using a modified protocol of Suzuki et al., 2006, J. Bioscience and Bioengineering 102: 572-574. A small amount of spores from each candidate was suspended in 25 μl of TE buffer and heated on high in a microwave oven for 1 minute. The microwaved spore suspension was used as a template in a PCR reaction to screen for the aspartic protease deletion. The reaction was composed of 1 μl of the spore suspension, 1 μl of 10 mM dNTPs, 12.5 μl of 2× ADVANTAGE® GC-Melt LA Buffer (Clontech, Mountain View, Calif., USA), 25 pmol of primer 066694 (16), 25 pmol of primer 066695 (Example 16), 1.25 units of ADVANTAGE® GC Genomic LA Polymerase Mix (Clontech, Mountain View, Calif., USA), and 9.25 μl water. The reaction was incubated in an EPPENDORF® MASTERCYCLER® programmed for 1 cycle at 95° C. for 10 minutes; 35 cycles each at 95° C. for 30 seconds, 60° C. for 30 seconds, and 72° C. for 4 minutes 30 seconds; 1 cycle at 72° C. for 5 minutes; and a 4° C. hold. The primers used in this screen were originally used to amplify the aspartic protease region. If the deletion vector was inserted into the aspartic protease locus, the amplified PCR fragment should be larger than the wild-type fragment since it contains the hph cassette used to disrupt the aspartic protease gene. The candidates that exhibited one larger band in the first Fungal Colony PCR screen were subjected to a second PCR screen using the primers shown below.

Primer 068331 (sense): (SEQ ID NO: 59) ATATCTCTCTCGAGGCCTGCTTATT Primer 067947 (antisense): (SEQ ID NO: 60) CTACATCGAAGCTGAAAGCACGAGA

Primer 068331 is upstream of the 5′ region of the aspartic protease gene contained in the deletion strain, and primer 067947 is in the hph cassette. Only those candidates that contain the aspartic protease disruption would produce a PCR fragment. The amplification reaction was composed of 1 μl of genomic DNA from the candidate (extracted according to Example 10), 1 μl of 10 mM dNTPs, 12.5 μl of 2× ADVANTAGE® GC-Melt LA Buffer, 25 pmol of primer 068331, 25 pmol of primer 067947, 0.25 μl 1.25 units of ADVANTAGE® GC Genomic LA Polymerase Mix, and 9.25 μl of water. The reaction was incubated in an EPPENDORF® MASTERCYCLER® programmed for 1 cycle at 95° C. for 2 minutes; 30 cycles each at 95° C. for 30 seconds, 55° C. for 30 seconds, and 72° C. for 2 minutes; 1 cycle at 72° C. for 5 minutes; and a 4° C. hold.

Southern blot analysis was performed to confirm the disruption of the aspartic protease gene by plasmid pAgJg111. Genomic DNA was extracted from the deletion strain and Trichoderma reesei strain 981-O-8 as described in Example 10. Two μg of genomic DNA from the deletion strain and Trichoderma reesei strain 981-O-8, as well as 1 ng of plasmid DNA from pAgJg111, were digested with Nco I and Pvu II. T. reesei strain 981-O-8 and pAgJg111 were included in the Southern blot as controls. The genomic DNA digestion reaction was composed of 2 μg of genomic DNA, 1 μl of Nco I, 1 μl of Pvu II, 5 μl of 10×NEB Buffer 2, and water to 50 μl. Both genomic DNA digestions were incubated at 37° C. for approximately 14-16 hours. Plasmid pAgJg111 was digested in a reaction composed of 1 ng of pAgJg111 DNA, 0.5 μl of Nco I, 0.5 μl of Pvu II, 2 μl of 10×NEB Buffer 2, and water to 20 μl. The digestion was incubated at 37° C. for approximately 1 hour.

The digestions were submitted to 0.7% agarose gel electrophoresis using TAE buffer and blotted onto NYTRAN® SuperCharge blotting membrane using a TURBOBLOTTER® for 14-16 hours following the manufacturer's recommendations. The membrane was hybridized with a 500 bp digoxigenin-labeled Trichoderma reesei 42 kDa aspartic protease probe, which was synthesized by incorporation of digoxigenin-11-dUTP by PCR using primers 068128 (sense) and 068129 (antisense) shown below.

Primer 068128 (sense): (SEQ ID NO: 61) AGTCAGGTTCAGCAGATCGCCAGGGATGG Primer 068129 (antisense): (SEQ ID NO: 62) GTGGTTCTCCAACGCCGCCAGCAGC

The amplification reaction was composed of 5 μl of 10× ThermoPol Reaction Buffer, 2.5 μl of PCR DIG Labeling Mix, 2 ng of pAgJg111, 50 pmol of primer 068128, 50 pmol of primer 068129, 2.5 μl of 10 mM dNTPs, 5 units of Taq DNA polymerase, and 35.5 μl of water. The reactions were incubated in an EPPENDORF® MASTERCYCLER® 5333 programmed for 1 cycle at 95° C. for 2 minutes; 30 cycles each at 95° C. for 30 seconds, 60° C. for 30 seconds, and 72° C. for 40 seconds; 1 cycle at 72° C. for 15 minutes; and a 4° C. hold. The PCR reaction product was purified by 1% agarose gel electrophoresis using TAE buffer, excised from the gel, and extracted using a QIAQUICK® Gel Extraction Kit according to the manufacturer's instructions. Incorporation of digoxigenin was indicated by increase in molecular mass.

Hybridization was performed in DIG Easy Hyb buffer at 42° C. for 15-17 hours. The membrane was then washed under high stringency conditions in 2×SSC plus 0.1% SDS for 5 minutes at room temperature followed by two washes in 0.5×SSC plus 0.1% SDS for 15 minutes each at 65° C. The probe-target hybrids were detected by chemiluminescent assay (Roche Molecular Biochemicals, Indianapolis, Ind., USA) following the manufacturer's instructions. The strain containing the aspartic protease deletion was designated Trichoderma reesei AgJg111-50.

Example 18: Aspergillus aculeatus GH10 Xylanase Expression in Aspartic Protease Deficient Strain AgJg111-50

To determine whether deletion of the 42 kDa aspartic protease was effective in eliminating degradation of the Aspergillus aculeatus GH10 xylanase, plasmid pSaMe-AaXYL (Example 14), which contains the Aspergillus aculeatus GH10 xylanase coding sequence, was transformed into Trichoderma reesei AgJg111-50. Protoplasts of T. reesei AgJg111-50 were generated as described in Example 12 and transformed with plasmid pSaMe-AaXYL. Twenty transformants containing the Aspergillus aculeatus GH10 xylanase were randomly selected from COVE plates and cultured in 125 ml shake flasks containing 25 ml of cellulase-inducing medium at pH 6.0 inoculated with spores of the transformants and incubated at 28° C. for 5 days with agitation at 200 rpm. Trichoderma reesei strain 981-O-8 and Trichoderma reesei AgJg111-50 were both run as controls. Culture broth samples were removed 5 days post-inoculation, centrifuged at 15,700×g for 10 minutes in a micro-centrifuge, and the supernatants transferred to new tubes.

The supernatants were analyzed by SDS-PAGE using an 8-16% CRITERION™ Tris-HCl gels with a CRITERION™ Cell. Five μl of day 5 samples were suspended in 2× concentration of Laemmli Sample Buffer and heated at 95° C. for 5 minutes in the presence of 5% β-mercaptoethanol. All samples were loaded onto the SDS-PAGE gels and subjected to electrophoresis in 1× Tris/Glycine/SDS running buffer. The resulting gels were stained with BIO-SAFE™ Coomassie Stain. SDS-PAGE analysis suggested that deletion of the aspartic protease gene for the production of Aspergillus aculeatus GH10 xylanase did not completely prevent proteolysis of the protein. The aspartic protease deletion strain T. reesei AgJg111-50 did not exhibit any unusual expression patterns of any protein and behaved similarly to the parent strain, Trichoderma reesei strain 981-O-8.

Example 19: Construction of Trichoderma reesei Trypsin-Like Serine Protease Gene Deletion Plasmid pAgJg116

The deletion vector pAgJg116 was constructed to disrupt expression of a Trichoderma reesei 25 kDa trypsin-like serine protease gene (SEQ ID NO: 5 for the DNA sequence and SEQ ID NO: 6 for the deduced amino acid sequence). Plasmid pAgJg116 was generated by first amplifying 5′ and 3′ flanking regions and cloning them into the vector pCR®2.1-TOPO®. The 5′ flanking region contains a region upstream of the 25 kDa serine protease coding region and part of the 25 kDa trypsin-like serine protease coding region. The 5′ flanking region was amplified using the primers 067518 (sense) and 067519 (antisense) shown below. Primer 067518 was engineered to contain Asc I and Not I sites on the 5′ end of the primer. Primer 067519 was engineered to contain an Asc I site on the 5′ end of the primer.

Primer 067518 (sense): (SEQ ID NO: 63) AAAGGCGCGCCGCGGCCGCGAAGAAGAAGAAGAACGTGAAAGAG Primer 067519 (antisense): (SEQ ID NO: 64) AAAGGCGCGCCCGGTCGAGCCGGCCACGGGGTCGGA

The 5′ region of the trypsin-like serine protease was amplified by PCR in a reaction composed of 175 μg of T. reesei genomic DNA (Example 10), 1 μl of Herculase II Fusion DNA Polymerase, 50 pmol of primer 067518, 50 pmol of primer 067519, 5 μl of 10 mM dNTPs, 5 μl of 5× Herculase II reaction buffer (Stratagene, LaJolla, Calif., USA), and 31 μl of water. The reaction was incubated in an EPPENDORF® MASTERCYCLER® programmed for 1 cycle at 95° C. for 2 minutes; 30 cycles each at 95° C. for 20 seconds, 60° C. for 20 seconds, and 72° C. for 45 seconds; 1 cycle at 72° C. for 3 minutes; and a 4° C. hold. A 1.5 kb PCR fragment was purified by 1% agarose gel electrophoresis using TAE buffer, excised from the gel, and extracted using QIAQUICK® Gel Extraction Kit according to the manufacturer's instructions. The gel purified PCR fragment was treated with Taq DNA polymerase to add 3′ A-overhangs to the fragment in a reaction composed of 5 μl of the purified PCR fragment, 1 μl of the 10× Thermopol Buffer, 0.5 μl of 10 mM dNTPs, 0.5 μl of Taq DNA polymerase, and 3 μl of water. The reaction was incubated at 72° C. for 15 minutes. The 5′ region of the trypsin-like serine protease fragment was cloned into pCR®2.1-TOPO® in a reaction composed of 2.5 μl of the 5′ trypsin-like serine protease region PCR fragment, 1 μl of Salt Solution, 1.5 μl of water, and 1 μl of pCR®2.1-TOPO®. The resulting plasmid was designated 5′SP-TOPO.

The 3′ region of the trypsin-like serine protease fragment was cloned into pCR®2.1-TOPO® using primers 067520 (sense) and 067521 (antisense) shown below. Primer 067520 was engineered to contain a Sbf I site on the 5′ end of the primer. Primer 067521 was engineered to contain Sbf I and Not I sites on the 5′ end of the primer.

Primer 067520 (Sense): (SEQ ID NO: 65) AAACCTGCAGGTCACCACCGCTGGCTGGTAAGCATCATC Primer 067521 (Antisense): (SEQ ID NO: 66) AAACCTGCAGGCGGCCGCACAAAGCTAGGAGTCTTGACGTGAT

The 3′ region of the trypsin-like serine protease gene was amplified by PCR in a reaction composed of 175 μg of T. reesei genomic DNA (Example 10), 1 μl of Herculase II Fusion DNA Polymerase, 50 pmol of primer 067520, 50 pmol of primer 067521, 5 μl of 10 mM dNTPs, 5 μl of 5× Herculase II reaction buffer, and 31 μl of water. The reaction was incubated in an EPPENDORF® MASTERCYCLER® programmed for 1 cycle at 95° C. for 2 minutes; 30 cycles each at 95° C. for 20 seconds, 60° C. for 20 seconds, and 72° C. for 45 seconds; 1 cycle at 72° C. for 3 minutes; and a 4° C. hold. A 1.5 kb PCR fragment was purified by 1% agarose gel electrophoresis using TAE buffer, excised from the gel, and extracted using a QIAQUICK® Gel Extraction Kit according to the manufacturer's instructions. The gel purified PCR fragment was treated with Taq DNA polymerase to add 3′ A-overhangs to the fragment in a reaction composed of 5 μl of the purified PCR fragment, 1 μl of the 10× Thermopol Buffer, 0.5 μl of 10 mM dNTPs, 0.5 μl of Taq DNA polymerase, and 3 μl of water. The reaction was incubated at 72° C. for 15 minutes. The 5′ region of the trypsin-like serine protease fragment was cloned into pCR®2.1-TOPO® according to the manufacturer's instruction in a reaction composed of 2.5 μl of the 5′ trypsin-like serine protease region PCR fragment, 1 μl of Salt Solution, 1.5 μl of water, and 1 μl of pCR®2.1-TOPO®. The resulting plasmid was designated 3′SP-TOPO.

Plasmid 5′SP-TOPO was digested with Asc I and cloned into Asc I digested plasmid pJfyS1579-41-11 (Example 9) in a reaction composed of 12.4 μg of digested 5′SP-TOPO plasmid DNA, 5 μl of Asc I, 10 μl of 10×NEB Buffer 4 (New England Biolabs, Inc, Ipswich, Mass., USA), and 55 μl of water. The restriction enzyme digestion was incubated at 37° C. for 2 hours. The digestion was purified by 1% agarose gel electrophoresis using TAE buffer, where a 1.5 kb fragment was excised from the gel and extracted using a QIAQUICK® Gel Extraction Kit according to the manufacturer's instructions. The Asc I digested 5′SP-TOPO fragment was ligated to the Asc I digested pJfyS1579-49-11 in a reaction composed of 282 ng of Asc I digested 5′SP-TOPO, 120 ng of Asc I digested pJfyS1579-49-11, 2 μl of Quick Ligase (New England Biolabs, Inc, Ipswich, Mass., USA), 15 μl of 2× Quick Ligase Buffer (New England Biolabs, Inc, Ipswich, Mass., USA), and 2 μl of water. The ligation reaction was incubated at room temperature for 15 minutes. The resulting plasmid was designated pJfyS1579+5′SP.

To construct plasmid pAgJg116, plasmids 3′SP-TOPO and pJfyS1579+5′SP were digested with Sbf I. The digestions were composed of 7.5 μg of pJfyS1579+5′SP or 12.5 μg of 3′SP-TOPO, 5 μl of Sbf I, 10 μl of 10×NEB Buffer 4, and 55 μl of water. Both digestion reactions were incubated at 37° C. overnight. Two μl of calf intestinal alkaline phosphatase (CIP) was added to the pJfyS1579+5′SP digestion reaction and incubated at 37° C. for an additional hour. A 9.5 kb fragment from pJfyS1579+5SP/Sbf I and a 1.5 kb fragment from 3SP-TOPO/Sbf I were purified by 0.8% agarose gel electrophoresis using TAE buffer, excised from the gel, and extracted using a QIAQUICK® Gel Extraction Kit according to the manufacturer's instructions. The Sbf I digested 3′SP-TOPO fragment was ligated to the Sbf I digested pJfyS1579+5′SP fragment in a reaction composed of 767 ng of Sbf I digested 3′SP-TOPO, 380 ng of Sbf I digested pJfyS1579+5′SP, 2 μl of Quick Ligase, 15 μl of 2× Quick Ligase Buffer, and 1 μl of water. The ligation reaction incubated at room temperature for 20 minutes. The resulting plasmid was designated pAgJg116 (FIG. 20).

Example 20: Generation of Trypsin-Like Serine Protease Gene Deletion Trichoderma reesei Strain AgJg116-19

Trichoderma reesei strain 981-O-8 protoplasts were transformed with Not I-linearized pAgJg116 using the method described in Example 12 to delete the trypsin-like serine protease gene. Ninety transformants were selected on PDA plates containing 25 μg of hygromycin B per ml. The transformants were sub-cultured to PDA plates to generate spores.

Transformants of Trichoderma reesei strain 981-O-8 containing the deletion vector pAgJg116 were cultured in 125 ml shake flasks containing 25 ml of cellulase-inducing medium at pH 6.0 inoculated with spores of the transformants and incubated at 28° C. for 5 days with agitation at 200 rpm. Trichoderma reesei strain 981-O-8 was run as a control. Culture broth samples were removed 5 days post-inoculation, centrifuged at 15,700×g for 10 minutes in a micro-centrifuge, and the supernatants transferred to new tubes.

The supernatants of each transformant were assayed for protease activity using the synthetic substrate Val-Leu-Lys 4-nitroanilide (Bachem AG, Bubendorf, Switzerland). The substrate was initially dissolved in dimethyl sulfoxide at a concentration of 100 mg/ml. The dissolved substrate was then diluted 200-fold into 100 mM NaCl-100 mM MOPS pH 7.0. The reaction was initiated by adding 10 μl of each transformant supernatant to 100 μl of the diluted substrate in a flat-bottomed 96-well plate. The reaction plate was incubated at 50° C. for 30 minutes and then the absorbance at 405 nm was measured using a SPECTRAMAX® Microplate Reader. Transformants exhibiting little to no protease activity were subjected to a PCR screen using the primers shown below.

Primer 068155 (sense): (SEQ ID NO: 67) GCTGTTTGGCCCTCGAAACTGCCGG Primer 067947 (antisense): (SEQ ID NO: 68) CTACATCGAAGCTGAAAGCACGAGA

Primer 068155 is upstream of the 5′ region of the trypsin-like serine protease gene contained in the deletion strain, and primer 067947 is in the hph cassette. Only those candidates that contain the trypsin-like serine protease disruption would produce a PCR fragment. The PCR screen was performed by Fungal Colony PCR according to the modified protocol described in Example 17. A small amount of spores from each candidate was suspended in 25 μl of TE buffer and heated on high in a microwave oven for 1 minute. The microwaved spore suspension was used as a template in a PCR reaction to screen for the aspartic protease deletion. The reaction was composed of 1 μl of the spore suspension, 1 μl of 10 mM dNTPs, 12.5 μl of 2× ADVANTAGE® GC-Melt LA Buffer, 25 pmol of primer 068155, 25 pmol of primer 067947, 1.25 units of ADVANTAGE® GC Genomic LA Polymerase Mix, and 9.25 μl water. The reaction was incubated in an EPPENDORF® MASTERCYCLER® programmed for 1 cycle at 95° C. for 10 minutes; 35 cycles each at 95° C. for 30 seconds, 60° C. for 30 seconds, and 72° C. for 2 minutes 30 seconds; 1 cycle at 72° C. for 5 minutes; and a 4° C. hold.

Southern blot analysis was performed to confirm the disruption of the 25 kDa trypsin-like serine protease gene by the vector pAgJg116. Genomic DNA was extracted from the deletion strains and Trichoderma reesei strain 981-O-8 according to Example 10. Two μg of genomic DNA from the deletion strains and Trichoderma reesei strain 981-O-8, along with 1 ng of plasmid DNA from pAgJg116 were digested with Nco I and Sac I. Trichoderma reesei strain 981-O-8 and pAgJg116 were included in the Southern blot as controls. The genomic DNA was digested in a reaction composed of 2 μg of genomic DNA, 1 μl of Nco I, 1 μl of Sac I, 5 μl of 10×NEB Buffer 1 (New England Biolabs, Inc, Ipswich, Mass., USA), 0.5 μl of 100×BSA, and water in a 50 μl reaction. Both digests were incubated at 37° C. for approximately 14-16 hours. Plasmid pAgJg116 was digested in a reaction composed of 1 ng of pAgJg116 DNA, 0.5 μl of Nco I, 0.5 μl of Sac I, 2 μl of 10×NEB Buffer 1, 0.2 μl of 100×BSA, and water in a 20 μl reaction. The digestion was incubated at 37° C. for approximately 1 hour and 30 minutes.

The digests were submitted to 0.7% agarose gel electrophoresis using TAE buffer and blotted onto NYTRAN® SuperCharge blotting membrane using a TURBOBLOTTER® for 14-16 hours following the manufacturer's recommendations. The membrane was hybridized with a 500 bp digoxigenin-labeled Trichoderma reesei 25 kDa trypsin-like serine protease probe, which was synthesized by incorporation of digoxigenin-11-dUTP during PCR using primers 068128 (sense) and 068129 (antisense) shown below.

Primer 068233 (sense): (SEQ ID NO: 69) CAACCCAAAGATATCGCCAGATCCA Primer 068234 (antisense): (SEQ ID NO: 70) ACGATAAACTCCCCCACGGCTGAAG

The amplification reaction was composed of 5 μl of 10× ThermoPol Reaction Buffer, 2.5 μl of PCR DIG Labeling Mix, 2 ng of pAgJg116, 50 pmol of primer 068233, 50 pmol of primer 068234, 2.5 μl of 10 mM dNTPs, 5 units of Taq DNA polymerase, and 35.5 μl water. The reaction was incubated in an EPPENDORF® MASTERCYCLER® programmed for 1 cycle at 95° C. for 2 minutes; 30 cycles each 95° C. for 30 seconds, 60° C. for 30 seconds, and 72° C. for 40 seconds; 1 cycle at 72° C. for 15 minutes; and a 4° C. hold. The PCR product was size-selected by 1.5% agarose gel electrophoresis using TAE buffer, excised from the gel, and extracted using a QIAQUICK® Gel Extraction Kit according to the manufacturer's instructions. Incorporation of digoxigenin was indicated by increase in molecular mass.

Hybridization was performed in DIG Easy Hyb buffer at 42° C. for 15-17 hours. The membrane was then washed under high stringency conditions in 2×SSC plus 0.1% SDS for 5 minutes at room temperature followed by two washes in 0.5×SSC plus 0.1% SDS for 15 minutes each at 65° C. The probe-target hybrids were detected by chemiluminescent assay following the manufacturer's instructions. Several transformants were confirmed to contain the trypsin-like serine protease deletion. One transformant was selected and designated Trichoderma reesei AgJg116-19.

Example 21: Aspergillus aculeatus GH10 Xylanase Expression in Trypsin-Like Serine Protease Deficient Strain AgJg116-19

To determine whether deletion of the 25 kDa trypsin-like serine protease was effective in preventing degradation of recombinantly expressed Aspergillus aculeatus GH10 xylanase, plasmid pSaMe-AaXYL (Example 14), which contains the Aspergillus aculeatus GH10 xylanase coding sequence, was transformed into the Trichoderma reesei AgJg116-19 strain. Protoplasts of Trichoderma reesei AgJg116-19 were generated as described in Example 12 and transformed with plasmid pSaMe-AaXYL. Thirty-six transformants containing the Aspergillus aculeatus GH10 xylanase were randomly selected from COVE plates and cultured in 125 ml shake flasks containing 25 ml of cellulase-inducing medium at pH 6.0 inoculated with spores of the transformants and incubated at 28° C. for 5 days with agitation at 200 rpm. Trichoderma reesei strain 981-O-8 and Trichoderma reesei AgJg116-19 were both run as controls. Culture broth samples were removed 5 days post-inoculation, centrifuged at 15,700×g for 10 minutes in a micro-centrifuge, and the supernatants transferred to new tubes.

The supernatants were analyzed by SDS-PAGE using an 8-16% CRITERION™ Tris-HCl gels with a CRITERION™ Cell. Five μl of day 5 samples were suspended in 2× concentration of Laemmli Sample Buffer and heated at 95° C. for 5 minutes in the presence of 5% β-mercaptoethanol. All samples were loaded onto the SDS-PAGE gels and subjected to electrophoresis in 1× Tris/Glycine/SDS running buffer. The resulting gels were stained with BIO-SAFE™ Coomassie Stain. SDS-PAGE analysis indicated that none of the transformants expressing the Aspergillus aculeatus GH10 xylanase produced any trace of degradation of the xylanase. Also, the trypsin-like serine protease deletion strain Trichoderma reesei AgJg116-19 did not exhibit any unusual expression patterns of any protein and behaved similarly to the parent strain, Trichoderma reesei strain 981-O-8. The deletion of the 25 kDa trypsin-like serine protease gene in Trichoderma reesei strain 981-O-8 appeared effective in eliminating degradation of the Aspergillus aculeatus GH10 xylanase.

Example 22: Construction of a Trichoderma reesei ku70 Gene Deletion Plasmid pAgJg115

The deletion vector pAgJg115 was constructed to disrupt the Trichoderma reesei ku70 gene. Disruption of the ku70 was required to increase the efficiency of gene targeting in Trichoderma reesei.

Plasmid pAgJg115 was generated by first amplifying 5′ and 3′ flanking regions and cloning them into the vector pCR®2.1-TOPO®. The 1.5 kb 5′ flank contains a region upstream of the ku70 gene as well as part of the ku70 coding sequence. The 5′ flanking region was amplified using primers 067491 (sense) and 067492 (antisense) shown below. Primer 067491 was engineered to contain Asc I and Not I sites on the 5′ end of the primer. Primer 067492 was engineered to contain an Asc I site on the 5′ end of the primer.

Primer 067491 (sense): (SEQ ID NO: 71) 5′-AAAGGCGCGCCGCGGCCGCCCATGGTGAGAAGCCGGGTTCGGGA G-3′ Primer 067492 (antisense): (SEQ ID NO: 72) 5′-AAAGGCGCGCC AGCCCTTGACAGTGATCTTGAGTCC-3′

The 5′ region of the ku70 gene was amplified by PCR in a reaction composed of 175 μg of T. reesei genomic DNA, 1 μl of Herculase II Fusion DNA Polymerase, 50 pmol of primer 067491, 50 pmol of primer 067492, 5 μl of 10 mM dNTPs, 10 μl of 5× Herculase II Reaction buffer (Stratagene), and 31 μl of water. The reaction was incubated in an EPPENDORF® MASTERCYCLER® programmed for 1 cycle at 95° C. for 2 minutes; 30 cycles each at 95° C. for 20 seconds, 61° C. for 20 seconds, and 72° C. for 45 seconds; 1 cycle at 72° C. for 3 minutes; and a 4° C. hold.

A 1.5 kb PCR fragment was purified by 1% agarose gel electrophoresis using TAE buffer, excised from the gel, and extracted using QIAQUICK® Gel Extraction Kit according to the manufacturer's instructions. The gel purified PCR fragment was treated with Taq DNA polymerase to add 3′ A-overhangs to the fragment in a reaction composed of 5 μl of the purified PCR fragment, 1 μl of 10× Thermopol Buffer, 0.5 μl of 10 mM dNTPs, 1 μl of Taq DNA polymerase, and 3 μl of water. The reaction was incubated at 72° C. for 15 minutes. The 5′ region of the ku70 fragment was cloned into pCR®2.1-TOPO® in a reaction composed of 2.5 μl of the 5′ flank ku70 PCR fragment, 1 μl of Salt Solution, 1 μl of water, and 1 μl of pCR®2.1-TOPO® and 2 μl of the reaction was transformed into ONE SHOT® TOP10 Chemically Competent E. coli cells (Invitrogen, Inc., Carlsbad, Calif., USA) according to the manufacturer's instructions. Transformants were selected on 2×YT agar plates supplemented with 100 μg of ampicillin per ml and incubated at 37° C. for 16 hours. The resulting plasmid was designated 5′ku70-TOPO.

The 3′ region of the ku70 fragment was cloned into pCR®2.1-TOPO® using primers 067493 (sense) and 067494 (antisense) shown below. Primer 067493 was engineered to contain a Sbf I site on the 5′ end of the primer. Primer 067494 was engineered to contain Sbf I and Not I sites on the 5′ end of the primer.

Primer 067493 (Sense): (SEQ ID NO: 73) 5′-AAACCTGCAGGACAACATTGTGCATCGGCAAACGCC-3′ Primer 067494 (Antisense): (SEQ ID NO: 74) 5′-AAACCTGCAGGCGGCCGCAAAGTGCCGGGGGTGOCCCAAGTCG-3′

The 3′ region of the ku70 gene was amplified by PCR in a reaction composed of 175 μg of T. reesei genomic DNA, 1 μl of Herculase II Fusion DNA Polymerase, 50 pmol of primer 067493, 50 pmol of primer 067494, 5 μl of 10 mM dNTPs, 10 μl of 5× Herculase II Reaction buffer, and 31 μl of water. The reaction was incubated in an EPPENDORF® MASTERCYCLER® programmed for 1 cycle at 95° C. for 2 minutes; 30 cycles each at 95° C. for 20 seconds, 61° C. for 20 seconds, and 72° C. for 45 seconds; 1 cycle at 72° C. for 3 minutes; and a 4° C. hold.

A 1.5 kb PCR fragment was purified by 1% agarose gel electrophoresis using TAE buffer, excised from the gel, and extracted using QIAQUICK® Gel Extraction Kit according to the manufacturer's instructions. The gel purified PCR fragment was treated with Taq DNA polymerase to add 3′ A-overhangs to the fragment in a reaction composed of 5 μl of the purified PCR fragment, 1 μl of the 10× Thermopol Buffer, 0.5 μl of 10 mM dNTPs, 1 μl of Taq DNA polymerase, and 3 μl of water. The reaction was incubated at 72° C. for 15 minutes. The 3′ region of the ku70 fragment was cloned into pCR®2.1-TOPO® in a reaction composed of 2.5 μl of the 3′ flank ku70 PCR fragment, 1 μl of Salt Solution, 1 μl of water, and 1 μl of pCR®2.1-TOPO® and 2 μl of the reaction was transformed into ONE SHOT® TOP10 Chemically Competent E. coli cells according to the manufacturer's instructions. Transformants were selected on 2×YT agar plates supplemented with 100 μg of ampicillin per ml and incubated at 37° C. for 16 hours. The resulting plasmid was designated 3′ku70-TOPO.

Plasmid 5′ku70-TOPO was digested with Asc I in order to be cloned into Asc I digested plasmid pJfyS1579-41-11 (Example 9) in a reaction composed of 14.6 μg of 5′ku70-TOPO plasmid DNA, 5 μl of Asc I, 10 μl of 10×NEB Buffer 4, and 55 μl of water. The restriction enzyme digestion was incubated at 37° C. for approximately 14-16 hours. The digestion was purified by 1% agarose gel electrophoresis using TAE buffer, where a 1.5 kb fragment was excised from the gel and extracted using a QIAQUICK® Gel Extraction Kit according to the manufacturer's instructions. The Asc I digested 5′ku70-TOPO fragment was ligated to the Asc I digested pJfyS1579-49-11 in a reaction composed of 329.6 ng of Asc I digested 5′ku70-TOPO, 120 ng of Asc I digested pJfyS1579-49-11, 2 μl of Quick Ligase, 15 μl of 2× Quick Ligase Buffer, and 2 μl of water. The ligation reaction was incubated at room temperature for 15 minutes and 4 μl of the ligation reaction was transformed into ONE SHOT® TOP10 Chemically Competent E. coli cells according to the manufacturer's instructions. Transformants were selected on 2×YT agar plates supplemented with 100 μg of ampicillin per ml and incubated at 37° C. for 16 hours. The resulting plasmid was designated pJfyS1579+5ku70.

To construct plasmid pAgJg115, plasmids 3′ku70-TOPO and pJfyS1579+5ku70 were digested with Sbf I. The digestion of pJfyS1579+5ku70 was composed of 3.98 μg of pJfyS1579+5ku70, 5 μl of Sbf I, 30 μl of 10×NEB Buffer 4, and 165 μl of water. The digestion of 3′ku70-TOPO was composed of 13.8 μg of 3′ku70-TOPO, 5 μl of Sbf I, 10 μl of 10×NEB Buffer 4, and 55 μl of water Both digestion reactions were incubated at 37° C. for 4 hours. A 9.5 kb fragment from pJfyS1579+5ku70/Sbf I and a 1.5 kb fragment from 3′ku70-TOPO/Sbf I were purified by 1% agarose gel electrophoresis using TAE buffer, excised from the gels, and extracted using a QIAQUICK® Gel Extraction Kit according to the manufacturer's instructions. The Sbf I digested 3′ku70-TOPO fragment was ligated to the Sbf I digested pJfyS1579+5ku70 fragment in a reaction composed of 335.8 ng of Sbf I digested 3′ku70-TOPO, 69.76 ng of Sbf I digested pJfyS1579+5ku70, 2 μl of Quick Ligase, 20 μl of 2× Quick Ligase Buffer, and 2 μl of water. The ligation reaction incubated at room temperature for 20 minutes and 5 μl of the ligation reaction was transformed into ONE SHOT® TOP10 Chemically Competent E. coli cells according to the manufacturer's instructions. Transformants were selected on 2×YT agar plates supplemented with 100 μg of ampicillin per ml and incubated at 37° C. for 16 hours The resulting plasmid was designated pAgJg115 (FIG. 21).

Example 23: Generation of a Ku70 Gene Disruption in Trichoderma reesei

Trichoderma reesei strain 981-O-8 protoplasts were transformed with Not I-linearized pAgJg115 using the method previously described in Example 12. Transformations were plated onto PDA+1 M sucrose and then overlayed with a thin layer containing PDA+10 mM uridine+hygromycin (100 μg/ml). One hundred twenty-nine transformants were sub-cultured onto PDA plates to generate spores.

Possible candidates of Trichoderma reesei strain 981-O-8 containing the pAgJg115 deletion vector in the ku70 locus, thereby disrupting the ku70 gene, were screened by fungal spore PCR using a modified protocol of Suzuki et al., 2006, supra. A small amount of spores from each candidate was suspended in 25 μl of TE buffer and heated on high in a microwave oven for 1 minute. The microwaved spore suspension was used as a template in a PCR reaction to screen for the serine protease deletion. The reaction was composed of 1 μl of the spore suspension, 1 μl of 10 mM dNTPs, 12.5 μl of 2× ADVANTAGE® GC-Melt LA Buffer, 25 pmol of primer 067946, 25 pmol of primer 067947, 1.25 units of ADVANTAGE® GC Genomic LA Polymerase Mix, and 9.25 μl water. The reaction was incubated in an EPPENDORF® MASTERCYCLER® programmed for 1 cycle at 95° C. for 10 minutes; 35 cycles each at 95° C. for 30 seconds, 60° C. for 30 seconds, and 72° C. for 2 minutes 30 seconds; 1 cycle at 72° C. for 5 minutes; and a 4° C. hold. Primer 067946 is located upstream of the 5′ flanking region and primer 067947 is located in the hpt marker; only the strains with the deletion cassette in the correct locus would yield a PCR product. Trichoderma reesei strain AgJg118-02 was identified in which the ku70 gene had been disrupted.

Primer 067946 (sense): (SEQ ID NO: 75) 5′-GCCAGGTGTCTGGCATGGCTGGCAAGCTGCGAC-3′ Primer 067947 (antisense): (SEQ ID NO: 76) 5′-CTACATCGAAGCTGAAAGCACGAGA-3′

Eight candidates were further evaluated by Southern blot analysis to confirm the disruption of the Trichoderma reesei ku70 gene. Genomic DNA was extracted from the deletion strains and Trichoderma reesei strain 981-O-8 as described in Example 10. Two μg of genomic DNA from the deletion strains and Trichoderma reesei strain 981-O-8, as well as 1 ng of plasmid DNA from pAgJg115, were digested with Hind III and Bam HI. T. reesei strain 981-O-8 and pAgJg115 were included in the Southern blot as controls. The genomic DNA digestion reaction was composed of 2 μg of genomic DNA, 1 μl of Hind III, 1 μl of Bam HI, 5 μl of 10×NEB Buffer 2, 0.5 μl of 100×BSA, and water to 50 μl. Both genomic DNA digestions were incubated at 37° C. for approximately 14-16 hours. Plasmid pAgJg115 was digested in a reaction composed of 1 ng of pAgJg111 DNA, 0.5 μl of Hind III, 0.5 μl of Bam HI, 2 μl of 10×NEB Buffer 2, 0.2 μl of 100×BSA, and water to 20 μl. The digestion was incubated at 37° C. for approximately 1 hour.

The digestions were submitted to 0.7% agarose gel electrophoresis using TAE buffer and blotted onto NYTRAN® SuperCharge blotting membrane using a TURBOBLOTTER® for 14-16 hours following the manufacturer's recommendations. The membrane was hybridized with a 500 bp digoxigenin-labeled Trichoderma reesei ku70 gene probe, which was synthesized by incorporation of digoxigenin-11-dUTP by PCR using primers 068067 (sense) and 068068 (antisense) shown below.

Primer 068067 (sense): (SEQ ID NO: 77) 5′-CATCCACTCGGAGATGCTGA-3′ Primer 068068 (antisense): (SEQ ID NO: 78) 5′-CGGAACTTGGTCTTTTCTGT-3′

The amplification reaction was composed of 5 μl of 10× ThermoPol Reaction Buffer, 2.5 μl of PCR DIG Labeling Mix, 2 ng of pAgJg115, 50 pmol of primer 068067, 50 pmol of primer 068068, 2.5 μl of 10 mM dNTPs, 5 units of Taq DNA polymerase, and 35.5 μl of water. The reactions were incubated in an EPPENDORF® MASTERCYCLER® 5333 programmed for 1 cycle at 95° C. for 2 minutes; 30 cycles each at 95° C. for 30 seconds, 55° C. for 30 seconds, and 72° C. for 40 seconds; 1 cycle at 72° C. for 15 minutes; and a 4° C. hold. The PCR reaction product was purified by 1% agarose gel electrophoresis using TAE buffer, excised from the gel, and extracted using a QIAQUICK® Gel Extraction Kit according to the manufacturer's instructions. Incorporation of digoxigenin was indicated by increase in molecular mass.

Hybridization was performed in DIG Easy Hyb buffer at 42° C. for 15-17 hours. The membrane was then washed under high stringency conditions in 2×SSC plus 0.1% SDS for 5 minutes at room temperature followed by two washes in 0.5×SSC plus 0.1% SDS for 15 minutes each at 65° C. The probe-target hybrids were detected by chemiluminescent assay (Roche Molecular Biochemicals, Indianapolis, Ind., USA) following the manufacturer's instructions. The strain containing the ku70 gene disruption was designated Trichoderma reesei AgJg115-104.

The disruption construct pAgJg115 contains the E. coli hygromycin phosphotransferase (hpt) gene and the Herpes simplex virus thymidine kinase (tk) gene flanked by direct repeats. The direct repeats were inserted to facilitate the excision of the hpt and tk selectable markers.

Spores from T. reesei AgJg115-104 were plated onto Trichoderma minimal medium plates containing 1 μM 5-fluoro-2′-deoxyuridine (FdU) at concentrations of 1×10⁵ and 1×10⁶ and incubated at 28° C. Fifteen isolates were sub-cultured onto Trichoderma minimal medium plates containing 1 μM FdU and incubated at 28° C. The fifteen isolates were then tested for sensitivity to hygromycin by sub-culturing them onto PDA plates with 25 μg/ml hygromycin and incubating them at 28° C. None of the isolates grew on the hygromycin plates, suggesting that the hpt and tk markers have been excised out of the strain.

To confirm the absence of the hpt and tk markers in T. reesei strain AgJg115-104, two isolates were evaluated by Southern blot. Genomic DNA was extracted from the marker-free disruption strains and T. reesei strain 981-O-8 as described in Example 10. Two μg of genomic DNA from the deletion strains and Trichoderma reesei strain 981-O-8 were digested with Hind III and Bam HI. T. reesei strain 981-O-8 was included in the Southern blot as a control. The genomic DNA digestion reaction was composed of 2 μg of genomic DNA, 1 μl of Hind III, 1 μl of Bam HI, 5 μl of 10×NEB Buffer 2, 0.5 μl of 100×BSA, and water to 50 μl. Both genomic DNA digestions were incubated at 37° C. for approximately 14-16 hours

The digestions were submitted to 0.7% agarose gel electrophoresis using TAE buffer and blotted onto NYTRAN® SuperCharge blotting membrane using a TURBOBLOTTER® for 14-16 hours following the manufacturer's recommendations. The membrane was hybridized with a 500 bp digoxigenin-labeled Trichoderma reesei ku70 gene probe as described above.

Hybridization was performed in DIG Easy Hyb buffer at 42° C. for 15-17 hours. The membrane was then washed under high stringency conditions in 2×SSC plus 0.1% SDS for 5 minutes at room temperature followed by two washes in 0.5×SSC plus 0.1% SDS for 15 minutes each at 65° C. The probe-target hybrids were detected by chemiluminescent assay (Roche Molecular Biochemicals, Indianapolis, Ind., USA) following the manufacturer's instructions. The marker free strain containing the ku70 gene disruption was designated Trichoderma reesei AgJg115-104-7B1.

Example 24: Generation of a Single Protease Deletion Trichoderma reesei Strain SMai-TrSP-30-22

Trichoderma reesei KU70-deficient strain AgJg115-104-7B1 protoplasts were transformed with Not I-linearized pDAtw18 (Example 11) using the method described in Example 12 to delete the Trichoderma reesei subtilisin-like serine protease gene. Thirty-six transformants were selected on PDA plates containing 10 μg of hygromycin B per ml. The transformants were sub-cultured to PDA plates to generate spores.

Fungal spore PCR using the modified protocol of Suzuki et al., 2006, supra was used to screen for transformants bearing putative deletion using a sense primer (067871) that was designed in the 5′-UTR of subtilisin-like serine protease gene and an antisense primer (067872) within the 3′-UTR.

Primer 067871 (Sense Primer): (SEQ ID NO: 79) 5′-ACTTCGGGGGATGGAAGTACATAAACTG-3′ Primer 067872 (AntiSense Primer): (SEQ ID NO: 80) 5′-CTCGATTCGCCATTAGATGTTTTATACCTG-3′

A 5 kb PCR product would be generated only upon the occurrence of a precise gene replacement at the subtilisin-like serine protease gene locus. If the cassette had integrated elsewhere in the genome, amplification of the wild-type 3 Kb subtilisin-like serine protease gene would result.

A small amount of spores from each candidate was suspended in 25 μl of TE buffer and heated on high in a microwave oven for 1 minute. The microwaved spore suspension was used as a template in a PCR reaction to screen for the subtilisin-like serine protease gene deletion. The reaction was composed of 1 μl of the spore suspension, 1 μl of 10 mM dNTPs, 12.5 μl of 2× ADVANTAGE® GC-Melt LA Buffer, 25 pmol of primer 067871, 25 pmol of primer 067872, 1.25 units of ADVANTAGE® GC Genomic LA Polymerase Mix, and 9.25 μl water. The reaction was incubated in an EPPENDORF® MASTERCYCLER® programmed for 1 cycle at 95° C. for 10 minutes; 35 cycles each at 94° C. for 30 seconds, 60° C. for 30 seconds, and 72° C. for 5 minutes 30 seconds; 1 cycle at 72° C. for 15 minutes; and a 4° C. hold.

Trichoderma reesei strain SMai-TrSP-30 was identified as deleted for the subtilisin-like serine protease gene.

The deletion construct pDAtw18 contains the positively-selectable hygromycin phosphoryl transferase (hpt) gene and the other encoding the negatively-selectable thymidine kinase (tk) gene, flanked by a direct repeats. The direct repeats were inserted to facilitate the excision of the hpt and tk selectable markers and generate a marker-free strain so it can be used as a host to delete a second protease gene.

Spores from T. reesei SMai-TrSP-30 were plated onto Trichoderma minimal medium plates containing 1 μM 5-fluoro-2′-deoxyuridine (FdU) at concentrations of 1×10⁵ and 1×10⁶ and incubated at 28° C. Twenty-three isolates were sub-cultured onto Trichoderma minimal medium plates containing 1 μM FdU and incubated at 28° C. All 23 isolates were then screened for the absence of the hpt and tk markers by fungal spore PCR in the same manner described in Example 26.

Southern blot analysis was performed to confirm the deletion of the subtilisin-like serine protease gene and the absence of the hpt and tk markers. Genomic DNA was extracted from the deletion strains and the T. reesei ku70 deletion strain AgJg115-104-7B1 as previously described in Example 10 and 2 μg of each were digested with 20 units of Nco I-HF™ for 16 hours at 37° C. Digested DNA was fractionated by 0.7% agarose gel electrophoresis using TAE buffer for 4 hours and blotted onto a NYTRAN™ SuperCharge membrane using a TURBOBLOTTER™ for 16 hours following the manufacturer's recommendations. The membrane was hybridized with a 502 bp digoxigenin-labeled subtilisin-like serine protease gene probe, which was synthesized by incorporation of digoxigenin-11-dUTP by PCR using primers 067911 (sense) and 067912 (antisense) described above.

The amplification reaction (50 μl) was composed of 1× ThermoPol Reaction Buffer, 5 μl of PCR DIG Labeling Mix, 10 ng of pDAtw18, 0.3 μM primer 067911, 0.3 μM primer 067912, and 2.5 units of Taq DNA polymerase. The reactions were incubated in an EPPENDORF® MASTERCYCLER® 5333 programmed for 30 cycles each at 95° C. for 30 seconds, 56° C. for 30 seconds, and 72° C. for 40 seconds (15 minute final extension). Five microliters of the PCR product was size-selected by 1.5% agarose gel electrophoresis using TAE buffer, stained with ethidium bromide, and visualized under a UV transilluminator. Incorporation of digoxigenin was indicated by increase in molecular mass.

Hybridization was performed in DIG Easy Hyb buffer (Roche Molecular Biochemicals, Indianapolis, Ind., USA) at 42° C. for 17 hours. The membrane was then washed under high stringency conditions in 2×SSC plus 0.1% SDS for 5 minutes at room temperature followed by two washes in 0.5×SSC plus 0.1% SDS for 15 minutes each at 65° C. The probe-target hybrids were detected by chemiluminescent assay (Roche Molecular Biochemicals, Indianapolis, Ind., USA) following the manufacturer's instructions. The marker-free strain containing the subtilisin-like serine protease gene deletion was designated Trichoderma reesei SMai-TrSP-30-22.

Example 25: Construction of Trichoderma reesei Trypsin-Like Serine Protease Gene Deletion Plasmid pAgJg117

The deletion vector pAgJg117 was constructed to delete the Trichoderma reesei 25 kDa trypsin-like serine protease gene. Plasmid pAgJg117 was generated by first amplifying 5′ and 3′ flanking regions and cloning them into the vector pCR®2.1-TOPO®. The 5′ flanking region contains a 1.5 kb region upstream of the 25 kDa serine protease coding region. The 5′ flanking region was amplified using primers 068616 (sense) and 068617 (antisense) shown below. Primer 068616 was engineered to contain Asc I and Not I sites on the 5′ end of the primer. Primer 068617 was engineered to contain an Asc I site on the 5′ end of the primer.

Primer 068616 (sense): (SEQ ID NO: 81) 5′-AAAGGCGCGCCGCGGCCGCAAAACACACACAATAACCAACCCCC A-3′ Primer 068617 (antisense): (SEQ ID NO: 82) 5′-AAAGGCGCGCC TGCGATGGAGGAAAAGCTGCGAGGGATGA-3′

The 5′ region of the trypsin-like serine protease was amplified by PCR in a reaction composed of 175 μg of T. reesei genomic DNA, 1 μl of PLATINUM® Pfx DNA polymerase, 50 pmol of primer 068616, 50 pmol of primer 068617, 1.5 μl of 10 mM dNTPs, 10 μl of 10×Pfx Amplification buffer, and 33.5 μl of water. The reaction was incubated in an EPPENDORF® MASTERCYCLER® programmed for 1 cycle at 98° C. for 3 minutes; 30 cycles each at 98° C. for 30 seconds, 60° C. for 30 seconds, and 72° C. for 1 minute 30 seconds; 1 cycle at 72° C. for 15 minutes; and a 4° C. hold. A 1.5 kb PCR fragment was purified by 1% agarose gel electrophoresis using TAE buffer, excised from the gel, and extracted using QIAQUICK® Gel Extraction Kit according to the manufacturer's instructions. The gel purified PCR fragment was treated with Taq DNA polymerase to add 3′ A-overhangs to the fragment in a reaction composed of 5 μl of the purified PCR fragment, 1 μl of the 10× Thermopol Buffer, 0.5 μl of 10 mM dNTPs, 0.5 μl of Taq DNA polymerase, and 3 μl of water. The reaction was incubated at 72° C. for 15 minutes. The 5′ region of the trypsin-like serine protease fragment was cloned into pCR®2.1-TOPO® in a reaction composed of 3 μl of the 5′ trypsin-like serine protease region PCR fragment, 1 μl of Salt Solution, 1 μl of water, and 1 μl of pCR®2.1-TOPO®. The resulting plasmid was designated 5′Serine.

The 3′ region of the trypsin-like serine protease fragment was cloned into pCR®2.1-TOPO® using primers 068618 (sense) and 068619 (antisense) shown below. Primer 068618 was engineered to contain a Sbf I site on the 5′ end of the primer. Primer 0668619 was engineered to contain Sbf I and Not I sites on the 5′ end of the primer.

Primer 068618 (Sense): (SEQ ID NO: 83) 5′-AAACCTGCAGGGCGATTCCCTGTGTTGGCAACCAAA-3′ Primer 068619 (Antisense): (SEQ ID NO: 84) 5′-AAACCTGCAGGCGGCCGCAAGAAATACTCAGGAAAGGTGCCCA-3′

The 3′ region of the trypsin-like serine protease gene was amplified by PCR in a reaction composed of 175 μg of T. reesei genomic DNA, 1 μl of PLATINUM® Pfx DNA polymerase, 50 pmol of primer 068618, 50 pmol of primer 068619, 1.5 μl of 10 mM dNTPs, 10 μl of 10×Pfx Amplification buffer, and 33.5 μl of water. The reaction was incubated in an EPPENDORF® MASTERCYCLER® programmed for 1 cycle at 98° C. for 3 minutes; 30 cycles each at 98° C. for 30 seconds, 60° C. for 30 seconds, and 72° C. for 1 minute 30 seconds; 1 cycle at 72° C. for 15 minutes; and a 4° C. hold. A 1.5 kb PCR fragment was purified by 1% agarose gel electrophoresis using TAE buffer, excised from the gel, and extracted using QIAQUICK® Gel Extraction Kit according to the manufacturer's instructions. The gel purified PCR fragment was treated with Taq DNA polymerase to add 3′ A-overhangs to the fragment in a reaction composed of 5 μl of the purified PCR fragment, 1 μl of the 10× Thermopol Buffer, 0.5 μl of 10 mM dNTPs, 0.5 μl of Taq DNA polymerase, and 3 μl of water. The reaction was incubated at 72° C. for 15 minutes. The 3′ region of the trypsin-like serine protease fragment was cloned into pCR®2.1-TOPO® in a reaction composed of 3 μl of the 5′ trypsin-like serine protease region PCR fragment, 1 μl of Salt Solution, 1 μl of water, and 1 μl of pCR®2.1-TOPO®. The resulting plasmid was designated 3′Serine.

Plasmid 5′Serine was digested with Asc I in order to be cloned into Asc I digested plasmid pJfyS1579-41-11 (Example 9) in a reaction composed of 12.4 μg of 5′Serine plasmid DNA, 5 μl of Asc I, 10 μl of 10×NEB Buffer 4, and 55 μl of water. The restriction enzyme digestion was incubated at 37° C. for 2 hours. The digestion was purified by 1% agarose gel electrophoresis using TAE buffer, where a 1.5 kb fragment was excised from the gel and extracted using a QIAQUICK® Gel Extraction Kit according to the manufacturer's instructions. The Asc I digested 5′Serine fragment was ligated to the Asc I digested pJfyS1579-49-11 in a reaction composed of 233.7 ng of Asc I digested 5′SP-TOPO, 160 ng of Asc I digested pJfyS1579-49-11, 3 μl of Quick Ligase, 25 μl of 2× Quick Ligase Buffer, and 3 μl of water. The ligation reaction was incubated at room temperature for 15 minutes. The resulting plasmid was designated 5′Serine+pJfyS1579.

To construct plasmid pAgJg117, plasmids 3′Serine and 5′Serine+pJfyS1579 were digested with Sbf I. The digestions were composed of 3.96 μg of 5′Serine+pJfyS1579 or 8.85 μg of 3′Serine, 4 μl of Sbf I, 10 μl of 10×NEB Buffer 4, and 56 μl of water. Both digestion reactions were incubated at 37° C. for two hours. One μl of calf intestinal alkaline phosphatase (CIP) was added to the 5′Serine+pJfyS1579 digestion reaction and incubated at 37° C. for an additional hour. A 9.5 kb fragment from 5′Serine+pJfyS1579/Sbf I and a 1.5 kb fragment from 3SP-TOPO/Sbf I were purified by 0.8% agarose gel electrophoresis using TAE buffer, excised from the gel, and extracted using a QIAQUICK® Gel Extraction Kit according to the manufacturer's instructions. The Sbf I digested 3′Serine fragment was ligated to the Sbf I digested 5′Serine+pJfyS1579 fragment in a reaction composed of 486 ng of Sbf I digested 3′Serine, 252 ng of Sbf I digested 5′Serine+pJfyS1579, 1 μl of Quick Ligase, 10 μl of 2× Quick Ligase Buffer, and 1.5 μl of water. The ligation reaction was incubated at room temperature for 20 minutes. The resulting plasmid was designated pAgJg117 (FIG. 22).

Example 26: Generation of a Double Protease Gene Deletion Trichoderma reesei Strain AgJg117-3-10A

Trichoderma reesei subtilisin-like serine protease gene deletion strain SMai-TrSP-30-22 protoplasts were generated and transformed with Not I-linearized pAgJg117 using the method previously described in Example 12 and plated onto PDA+1 M Sucrose+10 μg/ml of hygromycin. Six transformants were sub-cultured onto PDA plates to generate spores.

Possible candidates of Trichoderma reesei strain SMai-TrSP-30-22 containing the pAgJg117 deletion vector in the 25 kDa serine protease locus, thereby deleting the serine protease, were screened by fungal spore PCR using a modified protocol of Suzuki et al., 2006, supra. A small amount of spores from each candidate was suspended in 25 μl of TE buffer and heated on high in a microwave oven for 1 minute. The microwaved spore suspension was used as a template in a PCR reaction to screen for the serine protease deletion. The reaction was composed of 1 μl of the spore suspension, 1 μl of 10 mM dNTPs, 12.5 μl of 2× ADVANTAGE® GC-Melt LA Buffer, 25 pmol of primer 068980, 25 pmol of primer 067556, 1.25 units of ADVANTAGE® GC Genomic LA Polymerase Mix, and 9.25 μl water. The reaction was incubated in an EPPENDORF® MASTERCYCLER® programmed for 1 cycle at 95° C. for 10 minutes; 35 cycles each at 95° C. for 30 seconds, 55° C. for 30 seconds, and 72° C. for 5 minutes 45 seconds; 1 cycle at 72° C. for 15 minutes; and a 4° C. hold. The primers used in this screen were originally used as sequencing primers; primer 067556 is located at the end of the 5′ flanking region and primer 068980 is located at the beginning of the 3′ flanking region. If the deletion vector was inserted into the serine protease locus, the amplified PCR fragment should be larger than the wild-type fragment since it contains the hpt and tk cassette used to delete the serine protease gene. Trichoderma reesei strain AgJg117-3 was identified in which the serine protease had been deleted.

Primer 067556 (sense): (SEQ ID NO: 85) 5′-CTTCTCTTTCTGGCATTGAC-3′ Primer 068980 (antisense): (SEQ ID NO: 86) 5′-CTCGGAATCCTGCGGTTGCC-3′

The deletion construct pAgJg117 contains the E. coli hygromycin phosphotransferase (hpt) gene and the Herpes simplex virus thymidine kinase (tk) gene flanked by direct repeats. The direct repeats were inserted to facilitate the excision of the hpt and tk selectable markers and generate a marker-free strain so it can be used as a host to delete a third protease gene.

Spores from AgJg117-3 were plated onto Trichoderma minimal medium plates containing 1 μM 5-fluoro-2′-deoxyuridine (FdU) at concentrations of 1×10⁵ and 1×10⁶ and incubated at 28° C. Seventeen isolates were sub-cultured onto Trichoderma minimal medium plates containing 1 μM FdU and incubated at 28° C. Of the seventeen isolates, only seven had sporulated; those seven isolates were then sub-cultured onto PDA plates and incubated at 28° C. The seven isolates were then screened for the absence of the hpt and tk markers by fungal spore PCR in the same manner described above.

Southern blot analysis was performed to confirm the deletion of the 25 kDa serine protease gene and the absence of the hpt and tk markers. Genomic DNA was extracted from the deletion strain and T. reesei strain SMai-TrSP-30-22 as previously described in Example 10. Two μg of genomic DNA from the deletion strain, T. reesei strain SMai-TrSP-30-22, and T. reesei strain 981-O-8 were each digested with Hind III and Nco I. T. reesei strain 981-O-8 and T. reesei strain SMai-TrSP-30-22 were included in the Southern blot as controls. The genomic DNA digestion reaction was composed of 2 μg of genomic DNA, 1 μl of Nco I, 1 μl of Hind III, 3.5 μl of 10×NEB Buffer 2, and water to 35 μl. Both genomic DNA digestions were incubated at 37° C. for approximately 3.5 hours.

The digestions were submitted to 0.8% agarose gel electrophoresis using TAE buffer and blotted onto NYTRAN® SuperCharge blotting membrane using a TURBOBLOTTER® for approximately 5 hours following the manufacturer's recommendations. The membrane was hybridized with a 500 bp digoxigenin-labeled T. reesei 25 kDa serine protease probe, which was synthesized by incorporation of digoxigenin-11-dUTP by PCR using primers 069279 (sense) and 069280 (antisense) shown below.

Primer 069279 (sense): (SEQ ID NO: 87) 5′-GGCGCCTCAATCCAGAAGGTCGCAC-3′ Primer 069280 (antisense): (SEQ ID NO: 88) 5′-GTGTATGTAGTGAAACGAAGCATTCG-3′

The amplification reaction was composed of 5 μl of 10× ThermoPol Reaction Buffer, 2.5 μl of PCR DIG Labeling Mix, 1 ng of pAgJg117, 50 pmol of primer 069279, 50 pmol of primer 069280, 2.5 μl of 10 mM dNTPs, 5 units of Taq DNA polymerase, and 35.5 μl of water. The reactions were incubated in an EPPENDORF® MASTERCYCLER® 5333 programmed for 1 cycle at 95° C. for 2 minutes; 30 cycles each at 95° C. for 30 seconds, 55° C. for 30 seconds, and 72° C. for 40 seconds; 1 cycle at 72° C. for 15 minutes; and a 4° C. hold. The PCR reaction product was purified by 1% agarose gel electrophoresis using TAE buffer, excised from the gel, and extracted using a QIAQUICK® Gel Extraction Kit according to the manufacturer's instructions. Incorporation of digoxigenin was indicated by increase in molecular mass.

Hybridization was performed in DIG Easy Hyb buffer at 42° C. for 15-17 hours. The membrane was then washed under high stringency conditions in 2×SSC plus 0.1% SDS for 5 minutes at room temperature followed by two washes in 0.5×SSC plus 0.1% SDS for 15 minutes each at 65° C. The probe-target hybrids were detected by chemiluminescent assay (Roche Molecular Biochemicals, Indianapolis, Ind., USA) following the manufacturer's instructions. The strain containing the 25 kDa serine protease deletion was designated Trichoderma reesei AgJg117-3-10A.

Example 27: Construction of a Trichoderma reesei Aspartic Protease Gene Deletion Plasmid pAgJg118

The deletion vector pAgJg118 was constructed to delete the Trichoderma reesei 42 kDa aspartic protease gene. Plasmid pAgJg118 was generated by first amplifying 5′ and 3′ flanking regions and cloning them into the vector pCR®2.1-TOPO®. The 5′ flanking region contains a 1.5 kb region upstream of the 42 kDa aspartic protease coding region. The 5′ flanking region was amplified using primers 068620 (sense) and 068621 (antisense) shown below. Primer 068620 was engineered to contain Asc I and Not I sites on the 5′ end of the primer. Primer 068621 was engineered to contain an Asc I site on the 5′ end of the primer.

Primer 068620 (sense): (SEQ ID NO: 89) 5′-AAAGGCGCGCCGCGGCCGCTCGCTGTAACGAACTTCTGTCCGCA-3′ Primer 068621 (antisense): (SEQ ID NO: 90) 5′-AAAGGCGCGCCCTTGAATATCGGAGAAGGTTGCTCACGG-3′

The 5′ region of the aspartic protease gene was amplified by PCR in a reaction composed of 175 μg of T. reesei genomic DNA, 1 μl of PLATINUM® Pfx DNA polymerase, 50 pmol of primer 068620, 50 pmol of primer 068621, 1.5 μl of 10 mM dNTPs, 10 μl of 10×Pfx Amplification buffer, and 33.5 μl of water. The reaction was incubated in an EPPENDORF® MASTERCYCLER® programmed for 1 cycle at 98° C. for 3 minutes; 30 cycles each at 98° C. for 30 seconds, 60° C. for 30 seconds, and 72° C. for 1 minute 30 seconds; 1 cycle at 72° C. for 15 minutes; and a 4° C. hold. A 1.5 kb PCR fragment was purified by 1% agarose gel electrophoresis using TAE buffer, excised from the gel, and extracted using QIAQUICK® Gel Extraction Kit according to the manufacturer's instructions. The gel purified PCR fragment was treated with Taq DNA polymerase to add 3′ A-overhangs to the fragment in a reaction composed of 5 μl of the purified PCR fragment, 1 μl of the 10× Thermopol Buffer, 0.5 μl of 10 mM dNTPs, 1 μl of Taq DNA polymerase, and 3 μl of water. The reaction was incubated at 72° C. for 15 minutes. The 5′ region of the aspartic protease fragment was cloned into pCR®2.1-TOPO® in a reaction composed of 3 μl of the 5′ aspartic protease region PCR fragment, 1 μl of Salt Solution, 1 μl of water, and 1 μl of pCR®2.1-TOPO®. The resulting plasmid was designated 5′Aspartic.

The 3′ region of the aspartic protease fragment was cloned into pCR®2.1-TOPO® using primers 068622 (sense) and 068623 (antisense) shown below. Primer 068622 was engineered to contain a Sbf I site on the 5′ end of the primer. Primer 068623 was engineered to contain Sbf I and Not I sites on the 5′ end of the primer.

Primer 068622 (Sense): (SEQ ID NO: 91) AAACCTGCAGGGCGGCGATGGTGGACTTGTTTATGA-3′ Primer 068623 (Antisense): (SEQ ID NO: 92) AAACCTGCAGGCGGCCGCAGCAAGTGAGTATCGAGTTTGTAGG-3′

The 3′ region of the aspartic protease gene was amplified by PCR in a reaction composed of 175 μg of T. reesei genomic DNA, 1 μl of PLATINUM® Pfx DNA polymerase, 50 pmol of primer 068622, 50 pmol of primer 068623, 1.5 μl of 10 mM dNTPs, 10 μl of 10×Pfx Amplification buffer, and 33.5 μl of water. The reaction was incubated in an EPPENDORF® MASTERCYCLER® programmed for 1 cycle at 98° C. for 3 minutes; 30 cycles each at 98° C. for 30 seconds, 60° C. for 30 seconds, and 72° C. for 1 minute 30 seconds; 1 cycle at 72° C. for 15 minutes; and a 4° C. hold. A 1.5 kb PCR fragment was purified by 1% agarose gel electrophoresis using TAE buffer, excised from the gel, and extracted using QIAQUICK® Gel Extraction Kit according to the manufacturer's instructions. The gel purified PCR fragment was treated with Taq DNA polymerase to add 3′ A-overhangs to the fragment in a reaction composed of 5 μl of the purified PCR fragment, 1 μl of the 10× Thermopol Buffer, 0.5 μl of 10 mM dNTPs, 1 μl of Taq DNA polymerase, and 3 μl of water. The reaction was incubated at 72° C. for 15 minutes. The 3′ region of the aspartic protease fragment was cloned into pCR®2.1-TOPO® in a reaction composed of 3 μl of the 3′ aspartic protease region PCR fragment, 1 μl of Salt Solution, 1 μl of water, and 1 μl of pCR®2.1-TOPO®. The resulting plasmid was designated 3′Aspartic.

Plasmid 5′Aspartic was digested with Asc I in order to be cloned into Asc I digested plasmid pJfyS1579-41-11 (Example 9) in a reaction composed of 6.45 μg of 5′Aspartic plasmid DNA, 5 μl of Asc I, 10 μl of 10×NEB Buffer 4, and 61 μl of water. The restriction enzyme digestion was incubated at 37° C. for 4 hours. The digestion was purified by 1% agarose gel electrophoresis using TAE buffer, where a 1.5 kb fragment was excised from the gel and extracted using a QIAQUICK® Gel Extraction Kit according to the manufacturer's instructions. The Asc I digested 5′Aspartic fragment was ligated to the Asc I digested pJfyS1579-49-11 in a reaction composed of 307.2 ng of Asc I digested 5′Aspartic, 160 ng of Asc I digested pJfyS1579-49-11, 3 μl of Quick Ligase, 25 μl of 2× Quick Ligase Buffer, and 3 μl of water. The ligation reaction was incubated at room temperature for 15 minutes. The resulting plasmid was designated 5′Aspartic+pJfyS1579.

To construct plasmid pAgJg118, plasmids 3′Aspartic and 5′Aspartic+pJfyS1579 were digested with Sbf I. The digestions were composed of 3.5 μg of 5′Aspartic+pJfyS1579 or 5.3 μg of 3′Aspartic, 4 μl of Sbf I, 10 μl of 10×NEB Buffer 4, and 56 μl of water. Both digestion reactions were incubated at 37° C. for 1.5 hours. One μl of calf intestinal alkaline phosphatase (CIP) was added to the 5′Aspartic+pJfyS1579 digestion reaction and incubated at 37° C. for an additional hour. A 9.5 kb fragment from 5′Aspartic+pJfyS1579/Sbf I and a 1.5 kb fragment from 3′Aspartic/Sbf I were purified by 0.8% agarose gel electrophoresis using TAE buffer, excised from the gel, and extracted using a QIAQUICK® Gel Extraction Kit according to the manufacturer's instructions. The Sbf I digested 3′Aspartic fragment was ligated to the Sbf I digested 5′Aspartic+pJfyS1579 fragment in a reaction composed of 349.5 ng of Sbf I digested 3′Aspartic, 122.35 ng of Sbf I digested 5′Aspartic+pJfyS1579, 2 μl of Quick Ligase, 20 μl of 2× Quick Ligase Buffer, and 3 μl of water. The ligation reaction incubated at room temperature for 20 minutes and 3 μl of the ligation reaction was transformed into SOLOPACK® Gold Ultracompetent E. coli cells according to the manufacturer's instructions. Transformants were selected on 2×YT agar plates supplemented with 100 μg of ampicillin per ml and incubated at 37° C. for 16 hours. The resulting plasmid was designated pAgJg118 (FIG. 23).

Example 28: Generation of a Triple Protease Gene Deletion Trichoderma reesei Strain AgJg118-02-2E

Trichoderma reesei double protease deletion strain AgJg117-3-10A protoplasts were transformed with Not I-linearized pAgJg118 using the method previously described in Example 12 and plated onto PDA plates plus 1 M sucrose with 10 μg of hygromycin per ml. Six transformants were sub-cultured onto PDA plates to generate spores.

Possible candidates of T. reesei strain AgJg117-3-10A containing the pAgJg118 deletion vector in the 42 kDa aspartic protease locus, thereby deleting the aspartic protease, were screened by fungal spore PCR using the modified protocol of Suzuki et al., 2006, supra. A small amount of spores from each candidate was suspended in 25 μl of TE buffer and heated on high in a microwave oven for 1 minute. The microwaved spore suspension was used as a template in a PCR reaction to screen for the serine protease deletion. The reaction was composed of 1 μl of the spore suspension, 1 μl of 10 mM dNTPs, 12.5 μl of 2× ADVANTAGE® GC-Melt LA Buffer, 25 pmol of primer 069858, 25 pmol of primer 069859, 1.25 units of ADVANTAGE® GC Genomic LA Polymerase Mix, and 9.25 μl water. The reaction was incubated in an EPPENDORF® MASTERCYCLER® programmed for 1 cycle at 95° C. for 10 minutes; 35 cycles each at 95° C. for 30 seconds, 60° C. for 30 seconds, and 72° C. for 5 minutes 30 seconds; 1 cycle at 72° C. for 15 minutes; and a 4° C. hold. Primer 069858 is located at the end of the 5′ flanking region and primer 069859 is located at the beginning of the 3′ flanking region. If the deletion vector was inserted into the aspartic protease locus, the amplified PCR fragment should be larger than the wild-type fragment since it contains the hpt and tk cassette used to delete the serine protease gene. Trichoderma reesei AgJg118-02 was identified in which the aspartic protease had been deleted.

Primer 069858 (sense): (SEQ ID NO: 93) 5′-TCGGGGAGGATGGCGCAAACCGACCTTCCTAAA-3′ Primer 069859 (antisense): (SEQ ID NO: 94) 5′-GCACCTTACCCCTACGGACCACGAT-3′

The deletion construct pAgJg118 contains the E. coli hygromycin phosphotransferase (hpt) gene and the Herpes simplex virus thymidine kinase (tk) gene flanked by direct repeats. The direct repeats were inserted to facilitate the excision of the hpt and tk selectable markers and generate a clean deletion of the 42 kDa aspartic protease.

Spores from T. reesei AgJg118-02 were plated onto Trichoderma minimal medium plates containing 1 μM 5-fluoro-2′-deoxyuridine (FdU) at concentrations of 1×10⁵ and 1×10⁶ and incubated at 28° C. Ten isolates were sub-cultured onto PDA plates and incubated at 28° C. The ten isolates were then screened for the absence of the hpt and tk markers by fungal spore PCR in the same manner described above.

Southern blot analysis was performed to confirm the deletion of the 42 kDa aspartic protease gene and the absence of the hpt and tk markers. Genomic DNA was extracted from the deletion strain and T. reesei strain 981-O-8 as previously described in Example 10. Two μg of genomic DNA from the deletion strain and T. reesei strain 981-O-8 were digested with Nco I. T. reesei strain 981-O-8 was included in the Southern blot as a control. The genomic DNA digestion reaction was composed of 2 μg of genomic DNA, 1 μl of Nco I, 5 μl of 10×NEB Buffer 3, and water to 50 μl. Both genomic DNA digestions were incubated at 37° C. for approximately 14-16 hours.

The digestions were submitted to 0.8% agarose gel electrophoresis using TAE buffer and blotted onto NYTRAN® SuperCharge blotting membrane using a TURBOBLOTTER® for approximately 12-16 hours following the manufacturer's recommendations. The membrane was hybridized with a 500 bp digoxigenin-labeled T. reesei 42 kDa aspartic protease probe, which was synthesized by incorporation of digoxigenin-11-dUTP by PCR using primers 069860 (sense) and 069861 (antisense) shown below.

Primer 069860 (sense): (SEQ ID NO: 95) 5′-CTTCTATCTTGGGATGCTTCACGATACGTGA-3′ Primer 069861 (antisense): (SEQ ID NO: 96) 5′-CGCGCCCTTGAATATCGGAGAAGGT-3′

The amplification reaction was composed of 5 μl of 10×Taq Buffer, 2.5 μl of PCR DIG Labeling Mix, 5 ng of pAgJg118, 10 pmol of primer 069860, 10 pmol of primer 069861, 2.5 μl of 10 mM dNTPs, 5 units of Taq DNA polymerase, and 36.5 μl of water. The reactions were incubated in an EPPENDORF® MASTERCYCLER® 5333 programmed for 1 cycle at 95° C. for 2 minutes; 30 cycles each at 95° C. for 30 seconds, 56° C. for 30 seconds, and 72° C. for 40 seconds; 1 cycle at 72° C. for 15 minutes; and a 4° C. hold. The PCR reaction product was purified by 1% agarose gel electrophoresis using TAE buffer, excised from the gel, and extracted using a QIAQUICK® Gel Extraction Kit according to the manufacturer's instructions. Incorporation of digoxigenin was indicated by increase in molecular mass.

Hybridization was performed in DIG Easy Hyb buffer at 42° C. for 15-17 hours. The membrane was then washed under high stringency conditions in 2×SSC plus 0.1% SDS for 5 minutes at room temperature followed by two washes in 0.5×SSC plus 0.1% SDS for 15 minutes each at 65° C. The probe-target hybrids were detected by chemiluminescent assay (Roche Molecular Biochemicals, Indianapolis, Ind., USA) following the manufacturer's instructions. The strain containing the aspartic protease deletion was designated Trichoderma reesei AgJg118-02-2E.

Example 29: Fermentation of Trichoderma reesei AgJg117-3-10A and Trichoderma reesei AgJg118-02-2E

Spores of Trichoderma reesei AgJg117-3-10A and Trichoderma reesei AgJg118-02-2E from PDA plates were inoculated into 500 ml shake flasks, containing 100 ml of Shake Flask Medium. Trichoderma reesei strain 981-O-8 was run as a control under the same conditions. The flasks were placed into an orbital shaker at 28° C. for approximately 48 hours at which time 50 ml of the culture was added to an APPLIKON® three liter glass jacketed fermentor (Applikon Biotechnology, Inc., Foster City Calif. USA) that contains 1.8 liters of Fermentation Batch Medium. Fermentation Feed Medium was dosed at a rate of 0 to 4 g/l/hour for a period of 185 hours. The fermentation vessel was maintained at a temperature of 28° C. and pH was controlled using an APPLIKON® 1030 control system (Applikon Biotechnology, Inc., Foster City Calif. USA) to a set-point of 4.5+/−0.1. Air was added to the vessel at a rate of 1 vvm and the broth was agitated by Rushton impeller rotating at 1100 to 1300 rpm. At the end of the fermentation, whole broth was harvested from the vessel and centrifuged at 3000×g to remove the biomass. The supernatant was sterile filtered and stored at 5 to 10° C.

Example 30: Preparation of Aspergillus aculeatus Strain CBS 186.67 GH3 Beta-Xylosidase

The Aspergillus aculeatus strain CBS 186.67 GH3 beta-xylosidase was recombinantly prepared according to the following procedure.

To generate genomic DNA for PCR amplification, Aspergillus aculeatus CBS 186.67 was propagated on PDA agar plates by growing at 26° C. for 7 days. Spores harvested from the PDA plates were inoculated into 25 ml of YP+2% glucose medium in a baffled shake flask and incubated at 26° C. for 48 hours with agitation at 200 rpm.

Genomic DNA was isolated according to a modified FastDNA® SPIN protocol (Qbiogene, Inc., Carlsbad, Calif., USA). Briefly, a FastDNA® SPIN Kit for Soil (Qbiogene, Inc., Carlsbad, Calif., USA) was used in a FastPrep® 24 Homogenization System (MP Biosciences, Santa Ana, Calif., USA). Two ml of fungal material were harvested by centrifugation at 14,000×g for 2 minutes. The supernatant was removed and the pellet resuspended in 500 μl of deionized water. The suspension was transferred to a Lysing Matrix E FastPrep® tube (Qbiogene, Inc., Carlsbad, Calif., USA) and 790 μl of sodium phosphate buffer and 100 μl of MT buffer from the FastDNA® SPIN Kit were added to the tube. The sample was then secured in a FastPrep® Instrument (Qbiogene, Inc., Carlsbad, Calif., USA) and processed for 60 seconds at a speed of 5.5 m/sec. The sample was then centrifuged at 14,000×g for two minutes and the supernatant transferred to a clean EPPENDORF® tube. A 250 μl volume of PPS reagent from the FastDNA® SPIN Kit was added and then the sample was mixed gently by inversion. The sample was again centrifuged at 14,000×g for 5 minutes. The supernatant was transferred to a 15 ml tube followed by 1 ml of Binding Matrix suspension from the FastDNA® SPIN Kit and then mixed by inversion for two minutes. The sample was placed in a stationary tube rack and the silica matrix was allowed to settle for 3 minutes. A 500 μl volume of the supernatant was removed and discarded and then the remaining sample was resuspended in the matrix. The sample was then transferred to a SPIN filter tube from the FastDNA® SPIN Kit and centrifuged at 14,000×g for 1 minute. The catch tube was emptied and the remaining matrix suspension added to the SPIN filter tube. The sample was again centrifuged (14,000×g, 1 minute). A 500 μl volume of SEWS-M solution from the FastDNA® SPIN Kit was added to the SPIN filter tube and the sample was centrifuged at the same speed for 1 minute. The catch tube was emptied and the SPIN filter replaced in the catch tube. The unit was centrifuged at 14000×g for 2 minutes to “dry” the matrix of residual SEWS-M wash solution. The SPIN filter was placed in a fresh catch tube and allowed to air dry for 5 minutes at room temperature. The matrix was gently resuspended in 100 μl of DES (DNase/Pyrogen free water) with a pipette tip. The unit was centrifuged (14,000×g, 1 minute) to elute the genomic DNA followed by elution with 100 μl of 10 mM Tris, 0.1 mM EDTA, pH 8.0 by renewed centrifugation at 14000×g for 1 minute and the eluates were combined. The concentration of the DNA harvested from the catch tube was measured by a UV spectrophotometer at 260 nm.

The Aspergillus aculeatus beta-xylosidase gene was isolated by PCR using two cloning primers GH3-101f and GH3-101r, shown below, which were designed based on the publicly available Aspergillus aculeatus xyl2 full-length sequence (GenBank AB462375.1) for direct cloning using the IN-FUSION™ strategy.

Primer GH3-101f: (SEQ ID NO: 97) 5′-acacaactggggatccaccatggctgtggcggctcttgctctgctg g-3′ Primer GH3-101r: (SEQ ID NO: 98) 5′-agatctcgagaagcttaCTCATCCCCCGCCACCCCCTGCACCTC C-3′

A PCR reaction was performed with genomic DNA prepared from Aspergillus aculeatus CBS 186.67 in order to amplify the full-length gene. The PCR reaction was composed of 1 μl of genomic DNA, 0.75 μl of primer GH3-101.1f (10 μM), 0.75 μl of primer GH3-101.1r (10 μM), 3 μl of 5×HF buffer (Finnzymes Oy, Finland), 0.25 μl of 50 mM MgCl₂, 0.3 μl of 10 mM dNTP, 0.15 μl of PHUSION® DNA polymerase (New England Biolabs, Ipswich, Mass., USA), and PCR-grade water up to 15 μl. The PCR reaction was performed using a DYAD® PCR machine (Bio-Rad Laboratories, Inc., Hercules, Calif., USA) programmed for 2 minutes at 98° C. followed by 10 touchdown cycles at 98° C. for 15 seconds, 70° C. (−1° C./cycle) for 30 seconds, and 72° C. for 2 minutes 30 seconds; and 25 cycles each at 98° C. for 15 seconds, 60° C. for 30 seconds, 72° C. for 2 minutes 30 seconds, and 5 minutes at 72° C.

The reaction products were isolated by 1.0% agarose gel electrophoresis using TAE buffer where an approximately 2.4 kb PCR product band was excised from the gel and purified using a GFX® PCR DNA and Gel Band Purification Kit (GE Healthcare Life Sciences, Piscataway, N.J., USA) according to manufacturer's instructions. DNA corresponding to the Aspergillus aculeatus beta-xylosidase gene was cloned into the expression vector pDAu109 (WO 2005042735) linearized with Bam HI and Hind III, using an IN-FUSION™ Dry-Down PCR Cloning Kit (BD Biosciences, Palo Alto, Calif., USA) according to the manufacturer's instructions.

A 2.5 μl volume of the diluted ligation mixture was used to transform ONE SHOT® chemically competent TOP10 cells. Three colonies were selected on LB agar plates containing 100 μg of ampicillin per ml and cultivated overnight in 3 ml of LB medium supplemented with 100 μg of ampicillin per ml. Plasmid DNA was purified using an E.Z.N.A.® Plasmid Mini Kit (Omega Bio-Tek, Inc., Norcross, Ga., USA) according to the manufacturer's instructions. The Aspergillus aculeatus beta-xylosidase gene sequence was verified by Sanger sequencing before heterologous expression.

The coding sequence is 2454 bp including the stop codon. The gene does not contain introns. The encoded predicted protein is 817 amino acids. Using the SignalP program (Nielsen et al., 1997, Protein Engineering 10: 1-6), a signal peptide of 17 residues was predicted. The predicted mature protein contains 800 amino acids.

Protoplasts of Aspergillus oryzae MT3568 were prepared as described in WO 95/02043. A. oryzae MT3568 is an amdS (acetamidase) disrupted gene derivative of Aspergillus oryzae JaL355 (WO 2002/40694) in which pyrG auxotrophy was restored by disrupting the A. oryzae acetamidase (amdS) gene with the pyrG gene. One hundred microliters of protoplast suspension were mixed with 2.5-15 μg of the Aspergillus expression vector and 250 μl of 60% PEG 4000, 10 mM CaCl₂, and 10 mM Tris-HCl pH 7.5 were added and gently mixed. The mixture was incubated at 37° C. for 30 minutes and the protoplasts were spread on COVE sucrose (1 M) plates (Cove, 1996, Biochim. Biophys. Acta 133: 51-56) supplemented with 10 mM acetamide and 15 mM CsCl for transformant selection. After incubation for 4-7 days at 37° C. spores of several transformants were seeded on YP-2% maltodextrin medium. After 4 days cultivation at 30° C. culture broth was analyzed in order to identify the best transformants based on their ability to produce a large amount of active Aculeatus aculeatus beta-xylosidase. The screening was based on intensity of the band corresponding to the heterologous expressed protein determined by SDS-PAGE and activity of the enzyme on 4-nitrophenyl-beta-D-xylopyranoside (pNPX) as follows. Ten μl of culture broth was mixed with 90 μl of assay reagent containing 10 μl of 0.1% TWEEN® 20, 10 μl of 1 M sodium citrate pH 5, 4 μl of 100 mM of pNPX substrate (Sigma Aldrich, St. Louis, Mo., USA) solubilized in DMSO (0.4% final volume in stock solution), and filtered water. The assay was performed for 30 minutes at 37° C. and absorbance determined at 405 nm before and after addition of 100 μl of 1 M sodium carbonate pH 10. The highest absorbance values at 405 nm were correlated to the SDS-PAGE data for selection of the best transformant.

Spores of the best transformant designated A. oryzae EXP3611 were spread on COVE plates containing 0.01% TRITON® X-100 in order to isolate single colonies. The spreading was repeated twice in total on COVE sucrose medium (Cove, 1996, Biochim. Biophys. Acta 133: 51-56) containing 1 M sucrose and 10 mM sodium nitrate, supplemented with 10 mM acetamide and 15 mM CsCl. Fermentation was then carried out in 250 ml shake flasks using DAP-4C-1 medium for 4 days at 30° C. with shaking at 100 rpm. The fermentation broth was filtered using standard methods. Protein concentration was determined using a Microplate BCA™ Protein Assay Kit (Thermo Fischer Scientific, Waltham, Mass., USA) in which bovine serum albumin was used as a protein standard.

Example 31: Storage Stability of Broths from Trichoderma reesei AgJg117-3-10A and Trichoderma reesei AgJg118-02-2E at Elevated Temperatures

The broths of Trichoderma reesei AgJg117-3-10A, Trichoderma reesei AgJg118-02-2E, and Trichoderma reesei strain 981-O-8 (control) were evaluated for storage stability at elevated temperatures and compared to the stability of the parent strain. Fermentation broths obtained from Example 29 were sterile filtered (0.2 μM syringe filter, polyethersulfone membrane, GE Healthcare, Piscataway, N.J., USA), aliquoted into 1.8 mL Nunc CRYOTUBE™ Vials (Thermo Fisher Scientific, Waltham, Mass., USA) and flash frozen in liquid nitrogen. Vials were then stored at 40° C. or −80° C. (as a control) for two weeks. Following incubation, the samples were assayed for PCS hydrolysis activity.

Hydrolysis of PCS was conducted using 2.2 ml deep-well plates (Axygen, Union City, Calif., USA) in a total reaction volume of 1.0 ml. The hydrolysis was performed with 50 mg of PCS per ml of 50 mM sodium acetate pH 5.0 buffer containing 1 mM manganese sulfate and a dose response of the protease deletion strains and the parent strain (2, 4, 8, and 12 mg per gram of cellulose). Each reaction was supplemented with 5% addition by protein of an Aspergillus aculeatus beta-glucosidase (Example 30). Hydrolysis assays were performed in triplicate for 72 hours at 50° C. Following hydrolysis, samples were filtered with a 0.45 μm Multiscreen 96-well filter plate (Millipore, Bedford, Mass., USA) and filtrates analyzed for sugar content as described below.

Sugar concentrations of samples diluted in 0.005 M H₂SO₄ were measured after elution by 0.005 M H₂SO₄ with 0.05% w/w benzoic acid at a flow rate of 0.6 mL/min from a 4.6×250 mm AMINEX® HPX-87H column (Bio-Rad Laboratories, Inc., Hercules, Calif., USA) at 65° C. with quantitation by integration of glucose and cellobiose signal from refractive index detector (CHEMSTATION®, AGILENT® 1100 HPLC, Agilent Technologies, Santa Clara, Calif., USA) calibrated by pure sugar samples. The resultant equivalents were used to calculate the percentage of cellulose conversion for each reaction.

The degree of cellulose conversion was calculated using the following equation: % conversion=[glucose concentration+1.053×(cellobiose concentration)]/[(glucose concentration+1.053×(cellobiose concentration) in a limit digest]. The 1.053 factor for cellobiose takes into account the increase in mass when cellobiose is converted to glucose. Sixty mg of the T. reesei cellulolytic protein preparation per g of cellulose was used for the limit digest.

The results shown in FIG. 24 demonstrated that residual cellulase activity at 40° C. for two weeks of the broths from Trichoderma reesei AgJg117-3-10A and Trichoderma reesei AgJg118-02-2E were superior compared to the broth of the Trichoderma reesei strain 981-O-8 under the same conditions. To reach 80% conversion of the substrate required a 1.76 fold increase in protein loading for the parent strain with the sample incubated at 40° C. as compared to the control sample incubated at −80° C. Under the same conditions, there is 1.43 and 1.61 fold increase in protein loading for the triple and double protease deletion strain broths, respectively. Consequently, the triple protease deletion strain broth showed a 19% improvement in storage stability for two weeks at 40° C. The double protease deletion broth showed an 8.5% improvement when stored at 40° C. for two weeks.

Example 32: Generation of the Subtilisin-Like Serine Protease Deletion Vector pJfyS152

The 5′ flanking sequence of the T. reesei 981-O-8 subtilisin-like serine protease (pepC) gene (SEQ ID NO: 99 for the DNA sequence and SEQ ID NO: 100 for the deduced amino acid sequence) was amplified using PHUSION® Hot Start High-Fidelity DNA Polymerase (New England Biolabs, Ipswich, Mass., USA) and gene-specific forward and reverse primers shown below. The underlined portion is an Asc I site introduced for cloning and the region in italics represents an introduced extension corresponding to a homologous region of the site of vector insertion necessary for IN-FUSION® Cloning (Clontech, Palo Alto, Calif., USA).

Forward primer: (SEQ ID NO: 101) 5′-tcacatggtttaaac ggcgcgccGGTACTATATTAGAAAGGGGTTC C-3′ Reverse primer: (SEQ ID NO: 102) 5′-agccttgttttgtcg ggcgcgccGAAGAAGAGAAGAGGAGGAGGAT G-3′

The amplification reaction contained 150 ng of T. reesei 981-O-8 genomic DNA, 200 μm dNTP's, 0.4 μM primers, 1× PHUSION® GC Buffer (New England Biolabs, Ipswich, Mass., USA), and 2 units of PHUSION® DNA polymerase in a final volume of 50 μl. The amplification reaction was incubated in an EPPENDORF® MASTERCYCLER® programmed for 1 cycle at 98° C. for 2 minutes; 30 cycles each at 98° C. for 30 seconds, 57° C. for 30 seconds, and 72° C. for 1 minute 30 seconds; and one cycle at 72° C. for 7 minutes. PCR products were separated by 1% agarose gel electrophoresis using TAE buffer and a 2.2 kb fragment was excised and agarose was extracted using a NUCLEOSPIN® Extract II Kit (Machery-Nagel, Dueren, Germany) according to the manufacturer's protocol.

The 2.2 kb PCR product was inserted into Asc I-digested pJfyS1579-41-11 (Example 9) using an IN-FUSION® ADVANTAGE® PCR Cloning Kit (Clontech, Palo Alto, Calif., USA) according to the manufacturer's protocol. The IN-FUSION® reaction contained 1× IN-FUSION® Reaction buffer (Clontech, Palo Alto, Calif., USA), 150 ng of pJfyS1579-41-11, 100 ng of PCR product, and 1 μl of IN-FUSION® Enzyme (Clontech, Palo Alto, Calif., USA) in a 10 μl reaction volume. The reaction was incubated for 15 minutes at 37° C. and 15 minutes at 50° C. To the reaction 40 μl of TE were added. Two 2 μl were used to transform ONE SHOT® TOP10 competent cells according to the manufacturer's protocol. Transformants were screened by sequencing and one clone containing the insert with no PCR errors was identified and named pJfyS152A, Plasmid pJfyS152A was used to insert the 3′ flank of the pepC gene.

The 3′ pepC flanking sequence was amplified from T. reesei 981-O-8 genomic DNA (Example 13) using PHUSION® Hot Start High-Fidelity DNA Polymerase and gene-specific forward and reverse primers shown below. The underlined portion is a Sbf I site introduced for cloning and the region in italics represents an introduced extension corresponding to a homologous region of the site of vector insertion necessary for IN-FUSION® Cloning, and the bold portion is an introduced Pme I site for later removal of the bacterial propagation portion of the plasmid

Forward Primer: (SEQ ID NO: 103) 5′-cctagttggagtatt cctgcaggTCTATCTCTTTTGAGTAGTCCCC A-3′ Reverse primer: (SEQ ID NO: 104) 5′-tggccatatttaaat cctgcagg gtttaaacAGCTAGTGACTCGCGA TTTATCGT-3′

The amplification reaction contained 150 ng of T. reesei 981-O-8 genomic DNA, 200 μm dNTP's, 0.4 μM primers, 1× PHUSION® HF Buffer (New England Biolabs, Ipswich, Mass., USA) with 5 mM MgCl₂, and 2 units of PHUSION® DNA polymerase in a final volume of 50 μl. The amplification reaction was incubated in an EPPENDORF® MASTERCYCLER® programmed for 1 cycle at 98° C. for 2 minutes; 30 cycles each at 98° C. for 30 seconds, 56° C. for 30 seconds, and 72° C. for 1 minute 30 seconds; and one cycle at 72° C. for 7 minutes. PCR products were separated by 1% agarose gel electrophoresis using TAE buffer where a 2.2 kb fragment was excised and agarose was extracted using a NUCLEOSPIN® Extract II Kit according to the manufacturer's protocol.

The 2.2 kb PCR product was inserted into Sbf I-digested pJfyS152A using an IN-FUSION® ADVANTAGE® PCR Cloning Kit according to the manufacturers protocol. The IN-FUSION® reaction contained 1× IN-FUSION® Reaction buffer, 150 ng of pJfyS1579-41-11, 100 ng of the PCR product, and 1 μl of IN-FUSION® Enzyme in a 10 μl reaction volume. The reaction was incubated for 15 minutes at 37° C. and 15 minutes at 50° C. To the reaction 40 μl of TE were added and 2 μl was used to transform ONE SHOT® TOP10 competent cells according to the manufacturer's protocol. Transformants were screened by sequencing and one clone containing the insert with no PCR errors was identified and designated pJfyS152 (FIG. 25). Plasmid pJfyS152 was used to delete the pepC gene.

Example 33: Generation of Subtilisin-Like Serine Protease-Deleted Trichoderma reesei Strain JfyS152-1

Six transformants of T. reesei AgJg115-104-7B1 (Example 23) transformed with Pme I-digested and gel-purified pJfyS152 according to the procedure described in Example 12, were transferred from transformation plates with sterile inoculation loops to new plates containing PDA medium and grown at 28° C. for 7 days. All 6 transformants were then analyzed by Southern analysis. Genomic DNA from each of the 6 transformants was extracted as described in Example 21 and 2.5 μg of each were digested with 20 units of Nsi II and 20 units of Bgl II for 16 hours. Digestions were subjected to 0.9% agarose gel electrophoresis and blotted onto NYTRAN® SuperCharge blotting membrane using a TURBOBLOTTER® for approximately 12-16 hours following the manufacturer's recommendations. A PCR probe, hybridizing to the 3′ flanking sequence of the pepC gene, was generated using a PCR DIG Probe Synthesis Kit according to the manufacturer's protocol with the following forward and reverse primers:

Forward primer: (SEQ ID NO: 105) 5′-TGATTTCGTGGACAGCGTTTCTCGC-3′ Reverse primer: (SEQ ID NO: 106) 5′-TTGCCTTACAGCTGGCAACAATGGCGTC-3′

The amplification reaction was incubated in an EPPENDORF® MASTERCYCLER® programmed for 1 cycle at 95° C. for 2 minutes; 30 cycles each at 94° C. for 30 seconds, 59° C. for 30 seconds, and 72° C. for 40 seconds, and one cycle at 72° C. for 7 minutes. PCR products were separated by 1% agarose gel electrophoresis using TAE buffer and a 0.3 kb fragment was excised and agarose was extracted using a NUCLEOSPIN® Extract II Kit according to the manufacturer's protocol. The incorporation of digoxygenin was confirmed by the molecular weight shift of the labelled probe which ran at approximately 0.5 kb.

Hybridization was performed in DIG Easy Hyb buffer at 42° C. for 15-17 hours. The membrane was then washed under high stringency conditions in 2×SSC plus 0.1% SDS for 5 minutes at room temperature followed by two washes in 0.5×SSC plus 0.1% SDS for 15 minutes each at 65° C. The probe-target hybrids were detected by chemiluminescent assay (Roche Molecular Biochemicals, Indianapolis, Ind., USA) following the manufacturer's instructions

Southern analysis indicated that 3 of the 6 transformants harbored the deletion cassette in a single copy. The strain containing the pepC deletion was designated Trichoderma reesei JfyS152-1.

Example 34: Generation of the Pepsin-Like Aspartic Protease Deletion Vector pJfyS153

The 5′ flanking sequence of the Trichoderma reesei 981-O-8 pepsin-like aspartic protease gene (SEQ ID NO: 107 for the DNA sequence and SEQ ID NO: 108 for the deduced amino acid sequence) was amplified using PHUSION® Hot Start High-Fidelity DNA Polymerase New England Biolabs, Ipswich, Mass., USA) and gene-specific forward and reverse primers shown below. The underlined portion is an Asc I site introduced for cloning and the region in italics represents vector homology to the site of insertion for IN-FUSION®.

Forward primer: (SEQ ID NO: 109) 5′-tcacatggtttaaac ggcgcgccTTCCGGCTTCTTTTTATGTATACC T-3′ Reverse primer: (SEQ ID NO: 110) 5′-agccttgttttgtcg ggcgcgccAAGCTAGGAACCAGCCTCTTTGT A-3′

The amplification reaction contained 150 ng of Trichoderma reesei 981-O-8 genomic DNA, 200 μm dNTP's, 0.4 μM primers, 1× PHUSION® GC Buffer (New England Biolabs, Ipswich, Mass., USA) and 2 units of PHUSION® DNA polymerase (New England Biolabs, Ipswich, Mass., USA) in a final volume of 50 μl.

The amplification reaction was incubated in an EPPENDORF® MASTERCYCLER® programmed for 1 cycle at 95° C. for 2 minutes; 30 cycles each at 95° C. for 30 seconds, 57° C. for 30 seconds, and 72° C. for 1 minute 30 seconds; and one cycle at 72° C. for 7 minutes.

PCR products were separated by 1% agarose gel electrophoresis using TAE buffer and a 2.2 kb fragment was excised and agarose was extracted using a NUCLEOSPIN® Extract II Kit according to the manufacturer's protocol.

The 2.2 kb PCR product was inserted into Asc I-digested pJfyS1579-41-11 using an IN-FUSION® ADVANTAGE® PCR Cloning Kit according to the manufacturer's protocol. The IN-FUSION® reaction contained 1× IN-FUSION® Reaction buffer, 150 ng pJfyS1579-41-11, 100 ng PCR product and 1 μl IN-FUSION® Enzyme in a 10 μl reaction volume. The reaction was incubated for 15 minutes at 37° C. and 15 minutes at 50° C. To the reaction 40 μl of TE were added and 2 μl used to transform ONE SHOT® TOP 10 competent cells according to the manufacturer's protocol. Transformants were screened by sequencing and one clone containing the insert with no PCR errors was identified and designated pJfyS153A, and was used as the plasmid to insert the 3′ flank of the pepsin-like aspartic protease gene.

The 3′ flanking sequence of the pepsin-like aspartic protease gene was amplified from Trichoderma reesei 981-O-8 genomic DNA (Example 13) using PHUSION® Hot Start High-Fidelity DNA Polymerase (New England Biolabs, Ipswich, Mass., USA) and gene-specific forward and reverse primers shown below. The underlined portion is a Sbf I site introduced for cloning and the region in italics represents vector homology to the site of insertion for IN-FUSION®, and the bold portion is an introduced Pme I site for later removal of the bacterial propagation portion of the plasmid.

(SEQ ID NO: 111) 5′-ctagttggagtatt cctgcaggaGCCGAGCTCCTGAACGCTGAGAT T-3′ Reverse primer: (SEQ ID NO: 112) 5′-tggccatatttaaat cctgcag

GAGGGAAAAGGGCCG CTGCACGAT-3′

The amplification reaction contained 150 ng of Trichoderma reesei 981-O-8 genomic DNA, 200 μm dNTP's, 0.4 μM primers, 1× PHUSION® HF Buffer with 5 mM MgCl₂, and 2 units of PHUSION® DNA polymerase in a final volume of 50 μl.

The amplification reaction was incubated in an EPPENDORF® MASTERCYCLER® programmed for 1 cycle at 95° C. for 2 minutes; 30 cycles each at 95° C. for 30 seconds, 59° C. for 30 seconds, and 72° C. for 1 minute 30 seconds; and one cycle at 72° C. for 7 minutes.

PCR products were separated by 1% agarose gel electrophoresis using TAE buffer and a 1.5 kb fragment was excised and agarose was extracted using a NUCLEOSPIN® Extract II Kit according to the manufacturer's protocol.

The 1.5 kb PCR product was inserted into Sbf I-digested pJfyS153A using an IN-FUSION® ADVANTAGE® PCR Cloning Kit according to the manufacturer's protocol. The IN-FUSION® reaction contained 1× IN-FUSION® Reaction buffer, 150 ng of pJfyS1579-41-11, 100 ng of PCR product, and 1 μl of IN-FUSION® Enzyme in a 10 μl reaction volume. The reaction was incubated for 15 minutes at 37° C. and 15 minutes at 50° C. To the reaction 40 μl of TE were added and 2 μl used to transform ONE SHOT® TOP 10 competent cells according to the manufacturer's protocol (Invitrogen, Carlsbad, Calif., USA). Transformants were screened by sequencing and one clone containing the insert with no PCR errors was identified and designated pJfyS153 (FIG. 26), and was used to delete the pepsin-like aspartic protease gene.

Example 35: Generation of Pepsin-Like Aspartic Protease-Deleted Trichoderma reesei Strain JfyS153-6

Sixteen transformants of Trichoderma reesei AgJg115-104-7B1 (described in Example 23) were obtained when protoplasts were transformed with Pme I-digested and gel-purified pJfyS152 according to the procedure described in Example 12. All 16 were transferred from transformation plates with sterile inoculation loops to new plates containing PDA medium and grown at 28° C. for 4 days. The 16 transformants were analyzed by fungal spore PCR according to the method described in Example 23 with the following primers:

Forward Primer: (SEQ ID NO: 113) 5′-CGCGGAGGTGAGGTGTTGATGATG-3′ Reverse Primer 1 (wild-type): (SEQ ID NO: 114) 5′-CGGCGGTCTTTAAGGTGATGTCGC-3′ Reverse Primer 2 (deleted): (SEQ ID NO: 115) 5′-GTTTCAGGCAGGTCTTGCAACG-3′

The reaction was incubated in an EPPENDORF® MASTERCYCLER® programmed for 1 cycle at 98° C. for 5 minutes; 35 cycles each at 98° C. for 20 seconds, 53° C. for 30 seconds, and 72° C. for 3 minutes 30 seconds; 1 cycle at 72° C. for 7 minutes; and a 4° C. hold. PCR reactions were subjected to 1% Agarose Gel electrophoresis in TAE buffer.

The PCR primers were designed so that if the wild-type gene was intact the Forward and Reverse Primer 1 would anneal resulting in a 2.5 kb fragment and if the gene was deleted the Forward and Reverse Primer 2 would anneal resulting in a 3.5 kb fragment. The fungal spore PCR suggested that only one of the 16 transformants contained the deletion showing only the 3.5 kb fragment. This strain was subsequently analyzed by Southern analysis.

Genomic DNA was extracted as described in Example 21 and 2 μg were digested with 21.4 units of Nco I and 21.4 units of Bgl II for 16 hours. Digestions were subjected to 0.9% agarose gel electrophoresis in TAE buffer and blotted onto NYTRAN® SuperCharge blotting membrane using a TURBOBLOTTER® for approximately 12-16 hours following the manufacturer's recommendations. A PCR probe, hybridizing to the 3′ flanking sequence of the pepsin-like aspartic protease gene, was generated using a PCR DIG Probe Synthesis Kit according to the manufacturer's protocol (Roche Diagnostics, Indianapolis, Ind.) with the following forward and reverse primers:

Forward primer: (SEQ ID NO: 116) 5′-GAAGACAGTCCTACTGCTGCGGAG-3′ Reverse primer: (SEQ ID NO: 117) 5′-GTAGCTCTCCCCGTATAATGCAGG-3′

The amplification reaction was incubated in an EPPENDORF® MASTERCYCLER® programmed for 1 cycle at 95° C. for 2 minutes; 30 cycles each at 95° C. for 20 seconds, 57° C. for 30 seconds, and 72° C. for 40 seconds; and one cycle at 72° C. for 7 minutes.

PCR products were separated by 1.2% agarose gel electrophoresis using TAE buffer and a 0.6 kb fragment was excised and agarose was extracted using a Nucleospin Extract II® Kit according to the manufacturer's protocol. The incorporation of digoxygenin was confirmed by the molecular weight shift of the labelled probe which ran at approximately 0.6 kb.

Hybridization was performed in DIG Easy Hyb buffer at 42° C. for 15-17 hours. The membrane was then washed under high stringency conditions in 2×SSC plus 0.1% SDS for 5 minutes at room temperature followed by two washes in 0.5×SSC plus 0.1% SDS for 15 minutes each at 65° C. The probe-target hybrids were detected by chemiluminescent assay (Roche Molecular Biochemicals, Indianapolis, Ind., USA) following the manufacturer's instructions.

Southern analysis indicated that the strain harbored the deletion cassette in a single copy at the intended locus. The strain containing the pepsin-like protease deletion was designated Trichoderma reesei JfyS153-6.

The present invention is further described by the following numbered paragraphs:

[1] A mutant of a parent Trichoderma strain, comprising a polynucleotide encoding a polypeptide and one or more (several) genes selected from the group consisting of a first subtilisin-like serine protease gene, a first aspartic protease gene, a trypsin-like serine protease gene, a second subtilisin-like serine protease gene, and a second aspartic protease gene, wherein the one or more (several) genes are modified rendering the mutant strain deficient in the production of one or more (several) enzymes selected from the group consisting of a first subtilisin-like serine protease, a first aspartic protease, a trypsin-like serine protease, a second subtilisin-like serine protease, and a second aspartic protease, respectively, compared to the parent Trichoderma strain when cultivated under identical conditions.

[2] The mutant of paragraph 1, which comprises a modification of the first subtilisin-like serine protease gene.

[3] The mutant of paragraph 1 or 2, which comprises a modification of the first aspartic protease gene.

[4] The mutant of any of paragraphs 1-3, which comprises a modification of the trypsin-like serine protease gene.

[5] The mutant of any of paragraphs 1-4, which comprises a modification of the second subtilisin-like serine protease gene.

[6] The mutant of any of paragraphs 1-5, which comprises a modification of the second aspartic protease gene.

[7] The mutant of paragraph 1-6, which comprises a modification of the first subtilisin-like serine protease gene, the first aspartic protease gene, the trypsin-like serine protease gene, the second subtilisin-like serine protease gene, and the second aspartic protease gene.

[8] The mutant of any of paragraphs 1-7, wherein the polypeptide is native or foreign to the Trichoderma strain.

[9] The mutant of any of paragraphs 1-8, wherein the Trichoderma strain is selected from the group consisting of Trichoderma harzianum, Trichoderma koningii, Trichoderma longibrachiatum, Trichoderma reesei, and Trichoderma viride.

[10] The mutant of any of paragraphs 1-9, wherein the Trichoderma strain is Trichoderma reesei.

[11] The mutant of any of paragraphs 1-10, which produces at least 25% less of the one or more (several) enzymes selected from the group consisting of the first subtilisin-like serine protease, the first aspartic protease, the trypsin-like serine protease, the second subtilisin-like serine protease, and the second aspartic protease compared to the parent Trichoderma strain when cultivated under identical conditions.

[12] The mutant of any of paragraphs 1-10, which is completely deficient in the one or more (several) enzymes selected from the group consisting of the first subtilisin-like serine protease, the first aspartic protease, the trypsin-like serine protease, the second subtilisin-like serine protease, and the second aspartic protease compared to the parent Trichoderma strain when cultivated under identical conditions.

[13] The mutant of any of paragraphs 1-12, wherein the first subtilisin-like serine protease gene is selected from the group consisting of: (a) polypeptide comprising or consisting of an amino acid sequence having at least 60%, e.g., at least 65%, at least 70%, at least 75%, at least 80%, at least 85%, at least 90%, at least 95%, or 100% sequence identity to SEQ ID NO: 2 or the mature polypeptide thereof; (b) a polypeptide encoded by a polynucleotide that hybridizes under at least low stringency conditions, at least medium stringency conditions, at least medium-high stringency conditions, at least high stringency conditions, or at least very high stringency conditions with (i) SEQ ID NO: 1; (ii) the mature polypeptide coding sequence of SEQ ID NO: 1, (iii) the cDNA sequence of (i) or (ii), or (iv) a full-length complementary strand of (i), (ii), or (iii); and (c) a polypeptide encoded by a polynucleotide comprising or consisting of a nucleotide sequence having at least 60%, e.g., at least 65%, at least 70%, at least 75%, at least 80%, at least 85%, at least 90%, at least 95%, or 100% sequence identity to SEQ ID NO: 1 or the cDNA thereof, or the mature polypeptide coding sequence thereof.

[14] The mutant of any of paragraphs 1-13, wherein the first subtilisin-like serine protease comprises or consists of SEQ ID NO: 2 or the mature polypeptide thereof.

[15] The mutant of any of paragraphs 1-14, wherein the first aspartic protease gene is selected from the group consisting of: (a) a polypeptide comprising an amino acid sequence having at least 60%, e.g., at least 65%, at least 70%, at least 75%, at least 80%, at least 85%, at least 90%, at least 95%, or 100% sequence identity to SEQ ID NO: 4 or the mature polypeptide thereof; (b) a polypeptide encoded by a polynucleotide that hybridizes under at least low stringency conditions, at least medium stringency conditions, at least medium-high stringency conditions, at least high stringency conditions, or at least very high stringency conditions with (i) SEQ ID NO: 3; (ii) the mature polypeptide coding sequence of SEQ ID NO: 3, (iii) the cDNA sequence of (i) or (ii), or (iv) a full-length complementary strand of (i), (ii), or (iii); and (c) a polypeptide encoded by a polynucleotide comprising a nucleotide sequence having at least 60%, e.g., at least 65%, at least 70%, at least 75%, at least 80%, at least 85%, at least 90%, at least 95%, or 100% sequence identity to SEQ ID NO: 3 or the cDNA thereof, or the mature polypeptide coding sequence thereof.

[16] The mutant of any of paragraphs 1-15, wherein the first aspartic protease comprises or consists of SEQ ID NO: 4 or the mature polypeptide thereof.

[17] The mutant of any of paragraphs 1-16, wherein the trypsin-like serine protease gene is selected from the group consisting of: (a) a polypeptide comprising an amino acid sequence having at least 60%, e.g., at least 65%, at least 70%, at least 75%, at least 80%, at least 85%, at least 90%, at least 95%, or 100% sequence identity to SEQ ID NO: 6 or the mature polypeptide thereof; (b) a polypeptide encoded by a polynucleotide that hybridizes under at least low stringency conditions, at least medium stringency conditions, at least medium-high stringency conditions, at least high stringency conditions, or at least very high stringency conditions with (i) SEQ ID NO: 5; (ii) the mature polypeptide coding sequence of SEQ ID NO: 5, (iii) the cDNA sequence contained in (i) or (ii), or (iv) a full-length complementary strand of (i), (ii), or (iii); and (c) a polypeptide encoded by a polynucleotide comprising a nucleotide sequence having at least 60%, e.g., at least 65%, at least 70%, at least 75%, at least 80%, at least 85%, at least 90%, at least 95%, or 100% sequence identity to SEQ ID NO: 5 or the cDNA thereof, or the mature polypeptide coding sequence thereof.

[18] The mutant of any of paragraphs 1-17, wherein the trypsin-like serine protease comprises or consists of SEQ ID NO: 6 or the mature polypeptide thereof.

[19] The mutant of any of paragraphs 1-18, wherein the second subtilisin-like serine protease gene is selected from the group consisting of: (a) a polypeptide comprising or consisting of an amino acid sequence having at least 60%, e.g., at least 65%, at least 70%, at least 75%, at least 80%, at least 85%, at least 90%, at least 95%, or 100% sequence identity to SEQ ID NO: 100 or the mature polypeptide thereof; (b) a polypeptide encoded by a polynucleotide that hybridizes under at least low stringency conditions, at least medium stringency conditions, at least medium-high stringency conditions, at least high stringency conditions, or at least very high stringency conditions with (i) SEQ ID NO: 99; (ii) the mature polypeptide coding sequence of SEQ ID NO: 99, (iii) the cDNA sequence of (i) or (ii), or (iv) a full-length complementary strand of (i), (ii), or (iii); and (c) a polypeptide encoded by a polynucleotide comprising or consisting of a nucleotide sequence having at least 60%, e.g., at least 65%, at least 70%, at least 75%, at least 80%, at least 85%, at least 90%, at least 95%, or 100% sequence identity to SEQ ID NO: 100 or the cDNA thereof, or the mature polypeptide coding sequence thereof.

[20] The mutant of any of paragraphs 1-19, wherein the second subtilisin-like serine protease comprises or consists of SEQ ID NO: 100 or the mature polypeptide thereof.

[21] The mutant of any of paragraphs 1-20, wherein the second aspartic protease gene is selected from the group consisting of: (a) a polypeptide comprising an amino acid sequence having at least 60%, e.g., at least 65%, at least 70%, at least 75%, at least 80%, at least 85%, at least 90%, at least 95%, or 100% sequence identity to SEQ ID NO: 108 or the mature polypeptide thereof; (b) a polypeptide encoded by a polynucleotide that hybridizes under at least low stringency conditions, at least medium stringency conditions, at least medium-high stringency conditions, at least high stringency conditions, or at least very high stringency conditions with (i) SEQ ID NO: 3; (ii) the mature polypeptide coding sequence of SEQ ID NO: 107, (iii) the cDNA sequence of (i) or (ii), or (iv) a full-length complementary strand of (i), (ii), or (iii); and (c) a polypeptide encoded by a polynucleotide comprising a nucleotide sequence having at least 60%, e.g., at least 65%, at least 70%, at least 75%, at least 80%, at least 85%, at least 90%, at least 95%, or 100% sequence identity to SEQ ID NO: 107 or the cDNA thereof, or the mature polypeptide coding sequence thereof.

[22] The mutant of any of paragraphs 1-21, wherein the second aspartic protease comprises or consists of SEQ ID NO: 108 or the mature polypeptide thereof.

[23] A method of producing a polypeptide, comprising: cultivating a mutant of a parent Trichoderma strain in a medium for the production of the polypeptide, wherein the mutant strain comprises a polynucleotide encoding the polypeptide and one or more (several) genes selected from the group consisting of a first subtilisin-like serine protease gene, a first aspartic protease gene, a trypsin-like serine protease gene, a second subtilisin-like serine protease gene, and a second aspartic protease gene, wherein the one or more (several) genes are modified rendering the mutant strain deficient in the production of one or more (several) enzymes selected from the group consisting of a first subtilisin-like serine protease, a first aspartic protease, a trypsin-like serine protease, a second subtilisin-like serine protease, and a second aspartic protease, respectively, compared to the parent Trichoderma strain when cultivated under identical conditions; and recovering the polypeptide from the cultivation medium.

[24] The method of paragraph 23, wherein the mutant comprises a modification of the first subtilisin-like serine protease gene.

[25] The method of paragraph 23 or 24, wherein the mutant comprises a modification of the first aspartic protease gene.

[26] The method of any of paragraphs 23-25, wherein the mutant comprises a modification of the trypsin-like serine protease gene.

[27] The method of any of paragraphs 23-26, wherein the mutant comprises a modification of the second subtilisin-like serine protease gene.

[28] The method of any of paragraphs 23-27, wherein the mutant comprises a modification of the second aspartic protease gene.

[29] The method of any of paragraphs 23-28, wherein the mutant comprises a modification of the first subtilisin-like serine protease gene, the first aspartic protease gene, the trypsin-like serine protease gene, the second subtilisin-like serine protease gene, and the second aspartic protease gene.

[30] The method of any of paragraphs 23-29, wherein the polypeptide is native or foreign to the Trichoderma strain.

[31] The method of any of paragraphs 23-30, wherein the Trichoderma strain is selected from the group consisting of Trichoderma harzianum, Trichoderma koningii, Trichoderma longibrachiatum, Trichoderma reesei, and Trichoderma viride.

[32] The method of any of paragraphs 23-31, wherein the Trichoderma strain is Trichoderma reesei.

[33] The method of any of paragraphs 23-32, wherein the mutant strain produces at least 25% less of the one or more (several) enzymes selected from the group consisting of the first subtilisin-like serine protease, the first aspartic protease, the trypsin-like serine protease, the second subtilisin-like serine protease, and the second aspartic protease compared to the parent Trichoderma strain when cultivated under identical conditions.

[34] The method of any of paragraphs 23-32, wherein the mutant strain is completely deficient in the one or more (several) enzymes selected from the group consisting of the first subtilisin-like serine protease, the first aspartic protease, the trypsin-like serine protease, the second subtilisin-like serine protease, and the second aspartic protease compared to the parent Trichoderma strain when cultivated under identical conditions.

[35] The method of any of paragraphs 23-34, wherein the first subtilisin-like serine protease gene is selected from the group consisting of: (a) a polypeptide comprising or consisting of an amino acid sequence having at least 60%, e.g., at least 65%, at least 70%, at least 75%, at least 80%, at least 85%, at least 90%, at least 95%, or 100% sequence identity to SEQ ID NO: 2 or the mature polypeptide thereof; (b) a polypeptide encoded by a polynucleotide that hybridizes under at least low stringency conditions, at least medium stringency conditions, at least medium-high stringency conditions, high stringency conditions, or very high stringency conditions with (i) SEQ ID NO: 1; (ii) the mature polypeptide coding sequence of SEQ ID NO: 1, (iii) the cDNA sequence of (i) or (ii), or (iv) a full-length complementary strand of (i), (ii), or (iii); and (c) a polypeptide encoded by a polynucleotide comprising or consisting of a nucleotide sequence having at least 60%, e.g., at least 65%, at least 70%, at least 75%, at least 80%, at least 85%, at least 90%, at least 95%, or 100% sequence identity to SEQ ID NO: 1 or the cDNA thereof, or the mature polypeptide coding sequence thereof.

[36] The method of any of paragraphs 23-35, wherein the first subtilisin-like serine protease comprises or consists of SEQ ID NO: 2 or the mature polypeptide thereof.

[37] The method of any of paragraphs 23-36, wherein the first aspartic protease gene is selected from the group consisting of: (a) a polypeptide comprising an amino acid sequence having at least 60%, e.g., at least 65%, at least 70%, at least 75%, at least 80%, at least 85%, at least 90%, at least 95%, or 100% sequence identity to SEQ ID NO: 4 or the mature polypeptide thereof; (b) a polypeptide encoded by a polynucleotide that hybridizes under at least low stringency conditions, at least medium stringency conditions, at least medium-high stringency conditions, at least high stringency conditions, or at least very high stringency conditions with (i) SEQ ID NO: 3; (ii) the mature polypeptide coding sequence of SEQ ID NO: 3, (iii) the cDNA sequence of (i) or (ii), or (iv) a full-length complementary strand of (i), (ii), or (iii); and (c) a polypeptide encoded by a polynucleotide comprising a nucleotide sequence having at least 60%, e.g., at least 65%, at least 70%, at least 75%, at least 80%, at least 85%, at least 90%, at least 95%, or 100% sequence identity to SEQ ID NO: 3 or the cDNA thereof, or the mature polypeptide coding sequence thereof.

[38] The method of any of paragraphs 23-37, wherein the first aspartic protease comprises or consists of SEQ ID NO: 4 or the mature polypeptide thereof.

[39] The method of any of paragraphs 23-38, wherein the trypsin-like serine protease gene is selected from the group consisting of: (a) a polypeptide comprising an amino acid sequence having at least 60%, e.g., at least 65%, at least 70%, at least 75%, at least 80%, at least 85%, at least 90%, at least 95%, or 100% sequence identity to SEQ ID NO: 6 or the mature polypeptide thereof; (b) a polypeptide encoded by a polynucleotide that hybridizes under at least low stringency conditions, at least medium stringency conditions, at least medium-high stringency conditions, at least high stringency conditions, or at least very high stringency conditions with (i) SEQ ID NO: 5; (ii) the mature polypeptide coding sequence of SEQ ID NO: 5, (iii) the cDNA sequence contained in (i) or (ii), or (iv) a full-length complementary strand of (i), (ii), or (iii); and (c) a polypeptide encoded by a polynucleotide comprising a nucleotide sequence having at least 60%, e.g., at least 65%, at least 70%, at least 75%, at least 80%, at least 85%, at least 90%, at least 95%, or 100% sequence identity to SEQ ID NO: 5 or the cDNA thereof, or the mature polypeptide coding sequence thereof.

[40] The method of any of paragraphs 23-39, wherein the trypsin-like serine protease comprises or consists of SEQ ID NO: 6 or the mature polypeptide thereof.

[41] The method of any of paragraphs 23-40, wherein the second subtilisin-like serine protease gene is selected from the group consisting of: (a) a polypeptide comprising or consisting of an amino acid sequence having at least 60%, e.g., at least 65%, at least 70%, at least 75%, at least 80%, at least 85%, at least 90%, at least 95%, or 100% sequence identity to SEQ ID NO: 100 or the mature polypeptide thereof; (b) a polypeptide encoded by a polynucleotide that hybridizes under at least low stringency conditions, at least medium stringency conditions, at least medium-high stringency conditions, at least high stringency conditions, or at least very high stringency conditions with (i) SEQ ID NO: 99; (ii) the mature polypeptide coding sequence of SEQ ID NO: 99, (iii) the cDNA sequence of (i) or (ii), or (iv) a full-length complementary strand of (i), (ii), or (iii); and (c) a polypeptide encoded by a polynucleotide comprising or consisting of a nucleotide sequence having at least 60%, e.g., at least 65%, at least 70%, at least 75%, at least 80%, at least 85%, at least 90%, at least 95%, or 100% sequence identity to SEQ ID NO: 100 or the cDNA thereof, or the mature polypeptide coding sequence thereof.

[42] The method of any of paragraphs 23-41, wherein the second subtilisin-like serine protease comprises or consists of SEQ ID NO: 100 or the mature polypeptide thereof.

[43] The method of any of paragraphs 23-42, wherein the second aspartic protease gene is selected from the group consisting of: (a) a polypeptide comprising an amino acid sequence having at least 60%, e.g., at least 65%, at least 70%, at least 75%, at least 80%, at least 85%, at least 90%, at least 95%, or 100% sequence identity to SEQ ID NO: 108 or the mature polypeptide thereof; (b) a polypeptide encoded by a polynucleotide that hybridizes under at least low stringency conditions, at least medium stringency conditions, at least medium-high stringency conditions, at least high stringency conditions, or at least very high stringency conditions with (i) SEQ ID NO: 107; (ii) the mature polypeptide coding sequence of SEQ ID NO: 107, (iii) the cDNA sequence of (i) or (ii), or (iv) a full-length complementary strand of (i), (ii), or (iii); and (c) a polypeptide encoded by a polynucleotide comprising a nucleotide sequence having at least 60%, e.g., at least 65%, at least 70%, at least 75%, at least 80%, at least 85%, at least 90%, at least 95%, or 100% sequence identity to SEQ ID NO: 107 or the cDNA thereof, or the mature polypeptide coding sequence thereof.

[44] The method of any of paragraphs 23-43, wherein the second aspartic protease comprises or consists of SEQ ID NO: 108 or the mature polypeptide thereof.

[45] A method for obtaining a mutant of a parent Trichoderma strain, comprising: modifying one or more (several) genes selected from the group consisting of a first subtilisin-like serine protease gene, a first aspartic protease gene, a trypsin-like serine protease gene, a second subtilisin-like serine protease gene, and a second aspartic protease gene; and identifying a mutant strain from step (a) wherein the one or more (several) genes selected from the group consisting of the first subtilisin-like serine protease gene, the first aspartic protease gene, and the trypsin-like serine protease gene are modified rendering the mutant strain deficient in the production of one or more (several) enzymes selected from the group consisting of a first subtilisin-like serine protease, a first aspartic protease, a trypsin-like serine protease, a second subtilisin-like serine protease, and a second aspartic protease, respectively, compared to the parent Trichoderma strain when cultivated under identical conditions.

[46] The method of paragraph 45, wherein the mutant comprises a modification of the first subtilisin-like serine protease gene.

[47] The method of paragraph 45 or 46, wherein the mutant comprises a modification of the first aspartic protease gene.

[48] The method of any of paragraphs 45-47, wherein the mutant comprises a modification of the trypsin-like serine protease gene.

[49] The method of any of paragraphs 45-48, wherein the mutant comprises a modification of the second subtilisin-like serine protease gene.

[50] The method of any of paragraphs 45-49, wherein the mutant comprises a modification of the second aspartic protease gene.

[51] The method of any of paragraphs 45-50, wherein the mutant comprises a modification of the first subtilisin-like serine protease gene, the first aspartic protease gene, the trypsin-like serine protease gene, the second subtilisin-like serine protease gene, and the second aspartic protease gene.

[52] The method of any of paragraphs 45-51, wherein the polypeptide is native or foreign to the Trichoderma strain.

[53] The method of any of paragraphs 45-52, wherein the Trichoderma strain is selected from the group consisting of Trichoderma harzianum, Trichoderma koningii, Trichoderma longibrachiatum, Trichoderma reesei, and Trichoderma viride.

[54] The method of any of paragraphs 45-53, wherein the Trichoderma strain is Trichoderma reesei.

[55] The method of any of paragraphs 45-54, wherein the mutant strain produces at least 25% less of the one or more (several) enzymes selected from the group consisting of the first subtilisin-like serine protease, the first aspartic protease, the trypsin-like serine protease, the second subtilisin-like serine protease, and the second aspartic protease compared to the parent Trichoderma strain when cultivated under identical conditions.

[56] The method of any of paragraphs 45-54, wherein the mutant strain is completely deficient in the one or more (several) enzymes selected from the group consisting of the first subtilisin-like serine protease, the first aspartic protease, the trypsin-like serine protease, the second subtilisin-like serine protease, and the second aspartic protease compared to the parent Trichoderma strain when cultivated under identical conditions.

[57] The method of any of paragraphs 45-56, wherein the first subtilisin-like serine protease gene is selected from the group consisting of: (a) a polypeptide comprising or consisting of an amino acid sequence having at least 60%, e.g., at least 65%, at least 70%, at least 75%, at least 80%, at least 85%, at least 90%, at least 95%, or 100% sequence identity to SEQ ID NO: 2 or the mature polypeptide thereof; (b) a polypeptide encoded by a polynucleotide that hybridizes under at least low stringency conditions, at least medium stringency conditions, at least medium-high stringency conditions, at least high stringency conditions, or at least very high stringency conditions with (i) SEQ ID NO: 1; (ii) the mature polypeptide coding sequence of SEQ ID NO: 1, (iii) the cDNA sequence of (i) or (ii), or (iv) a full-length complementary strand of (i), (ii), or (iii); and (c) a polypeptide encoded by a polynucleotide comprising or consisting of a nucleotide sequence having at least 60%, e.g., at least 65%, at least 70%, at least 75%, at least 80%, at least 85%, at least 90%, at least 95%, or 100% sequence identity to SEQ ID NO: 1 or the cDNA thereof, or the mature polypeptide coding sequence thereof.

[58] The method of any of paragraphs 45-57, wherein the first subtilisin-like serine protease comprises or consists of SEQ ID NO: 2 or the mature polypeptide thereof.

[59] The method of any of paragraphs 45-58, wherein the first aspartic protease gene is selected from the group consisting of: (a) a polypeptide comprising an amino acid sequence having at least 60%, e.g., at least 65%, at least 70%, at least 75%, at least 80%, at least 85%, at least 90%, at least 95%, or 100% sequence identity to SEQ ID NO: 4 or the mature polypeptide thereof; (b) a polypeptide encoded by a polynucleotide that hybridizes under at least low stringency conditions, at least medium stringency conditions, at least medium-high stringency conditions, at least high stringency conditions, or at least very high stringency conditions with (i) SEQ ID NO: 3; (ii) the mature polypeptide coding sequence of SEQ ID NO: 3, (iii) the cDNA sequence of (i) or (ii), or (iv) a full-length complementary strand of (i), (ii), or (iii); and (c) a polypeptide encoded by a polynucleotide comprising a nucleotide sequence having at least 60%, e.g., at least 65%, at least 70%, at least 75%, at least 80%, at least 85%, at least 90%, at least 95%, or 100% sequence identity to SEQ ID NO: 3 or the cDNA thereof, or the mature polypeptide coding sequence thereof.

[60] The method of any of paragraphs 45-59, wherein the first aspartic protease comprises or consists of SEQ ID NO: 4 or the mature polypeptide thereof.

[61] The method of any of paragraphs 45-60, wherein the trypsin-like serine protease gene is selected from the group consisting of: (a) a polypeptide comprising an amino acid sequence having at least 60%, e.g., at least 65%, at least 70%, at least 75%, at least 80%, at least 85%, at least 90%, at least 95%, or 100% sequence identity to SEQ ID NO: 6 or the mature polypeptide thereof; (b) a polypeptide encoded by a polynucleotide that hybridizes under at least low stringency conditions, at least medium stringency conditions, at least medium-high stringency conditions, high stringency conditions, or very high stringency conditions with (i) SEQ ID NO: 5; (ii) the mature polypeptide coding sequence of SEQ ID NO: 5, (iii) the cDNA sequence contained in (i) or (ii), or (iv) a full-length complementary strand of (i), (ii), or (iii); and (c) a polypeptide encoded by a polynucleotide comprising a nucleotide sequence having at least 60%, e.g., at least 65%, at least 70%, at least 75%, at least 80%, at least 85%, at least 90%, at least 95%, or 100% sequence identity to SEQ ID NO: 5 or the cDNA thereof, or the mature polypeptide coding sequence thereof.

[62] The method of any of paragraphs 45-61, wherein the trypsin-like serine protease comprises or consists of SEQ ID NO: 6 or the mature polypeptide thereof.

[63] The method of any of paragraphs 45-62, wherein the second subtilisin-like serine protease gene is selected from the group consisting of: (a) a polypeptide comprising or consisting of an amino acid sequence having at least 60%, e.g., at least 65%, at least 70%, at least 75%, at least 80%, at least 85%, at least 90%, at least 95%, or 100% sequence identity to SEQ ID NO: 100 or the mature polypeptide thereof; (b) a polypeptide encoded by a polynucleotide that hybridizes under at least low stringency conditions, at least medium stringency conditions, at least medium-high stringency conditions, at least high stringency conditions, or at least very high stringency conditions with (i) SEQ ID NO: 99; (ii) the mature polypeptide coding sequence of SEQ ID NO: 99, (iii) the cDNA sequence of (i) or (ii), or (iv) a full-length complementary strand of (i), (ii), or (iii); and (c) a polypeptide encoded by a polynucleotide comprising or consisting of a nucleotide sequence having at least 60%, e.g., at least 65%, at least 70%, at least 75%, at least 80%, at least 85%, at least 90%, at least 95%, or 100% sequence identity to SEQ ID NO: 100 or the cDNA thereof, or the mature polypeptide coding sequence thereof.

[64] The method of any of paragraphs 45-63, wherein the second subtilisin-like serine protease comprises or consists of SEQ ID NO: 100 or the mature polypeptide thereof.

[65] The method of any of paragraphs 45-64, wherein the second aspartic protease gene is selected from the group consisting of: (a) a polypeptide comprising an amino acid sequence having at least 60%, e.g., at least 65%, at least 70%, at least 75%, at least 80%, at least 85%, at least 90%, at least 95%, or 100% sequence identity to SEQ ID NO: 108 or the mature polypeptide thereof; (b) a polypeptide encoded by a polynucleotide that hybridizes under at least low stringency conditions, at least medium stringency conditions, at least medium-high stringency conditions, at least high stringency conditions, or at least very high stringency conditions with (i) SEQ ID NO: 3; (ii) the mature polypeptide coding sequence of SEQ ID NO: 107, (iii) the cDNA sequence of (i) or (ii), or (iv) a full-length complementary strand of (i), (ii), or (iii); and (c) a polypeptide encoded by a polynucleotide comprising a nucleotide sequence having at least 60%, e.g., at least 65%, at least 70%, at least 75%, at least 80%, at least 85%, at least 90%, at least 95%, or 100% sequence identity to SEQ ID NO: 107 or the cDNA thereof, or the mature polypeptide coding sequence thereof.

[66] The method of any of paragraphs 45-65, wherein the second aspartic protease comprises or consists of SEQ ID NO: 108 or the mature polypeptide thereof.

The invention described and claimed herein is not to be limited in scope by the specific aspects herein disclosed, since these aspects are intended as illustrations of several aspects of the invention. Any equivalent aspects are intended to be within the scope of this invention. Indeed, various modifications of the invention in addition to those shown and described herein will become apparent to those skilled in the art from the foregoing description. Such modifications are also intended to fall within the scope of the appended claims. In the case of conflict, the present disclosure including definitions will control. Various references are cited herein, the disclosures of which are incorporated by reference in their entireties. 

What is claimed is:
 1. An isolated mutant of a parent Trichoderma strain, comprising a polynucleotide encoding a polypeptide and a first aspartic protease gene, wherein the first aspartic protease gene is modified rendering the mutant strain at least 95% deficient in the production of the first aspartic protease compared to the parent Trichoderma strain when cultivated under identical conditions; wherein the first aspartic protease is selected from the group consisting of: (a) a polypeptide comprising an amino acid sequence having at least 95% sequence identity to SEQ ID NO: 4 or amino acids 21 to 407 of SEQ ID NO: 4; and (b) a polypeptide encoded by a polynucleotide comprising a nucleotide sequence having at least 95% sequence identity to SEQ ID NO: 3 or nucleotides 61 to 1299 of SEQ ID NO: 3, or the cDNA thereof; and wherein the polypeptide is heterologous to the parent Trichoderma strain.
 2. The isolated mutant of claim 1, wherein the parent Trichoderma strain is selected from the group consisting of Trichoderma harzianum, Trichoderma koningii, Trichoderma longibrachiatum, Trichoderma reesei, and Trichoderma viride.
 3. The isolated mutant of claim 1, wherein the parent Trichoderma strain is Trichoderma reesei.
 4. The isolated mutant of claim 1, which is completely deficient in the first aspartic protease compared to the parent Trichoderma strain when cultivated under identical conditions.
 5. The isolated mutant of claim 1, wherein the first aspartic protease comprises SEQ ID NO: 4 or amino acids 21 to 407 of SEQ ID NO:
 4. 6. The isolated mutant of claim 1, which further comprises a first subtilisin-like serine protease gene, a trypsin-like serine protease gene, a second subtilisin-like serine protease gene, and a second aspartic protease gene, wherein one or more of the first subtilisin-like serine protease gene, the trypsin-like serine protease gene, the second subtilisin-like serine protease gene, and the second aspartic protease gene are modified rendering the mutant strain at least 95% deficient in the production of one or more of the first subtilisin-like serine protease, the trypsin-like serine protease, the second subtilisin-like serine protease, and the second aspartic protease, respectively, compared to the parent Trichoderma strain when cultivated under identical conditions; wherein the first subtilisin-like serine protease is selected from the group consisting of: (a) a polypeptide comprising an amino acid sequence having at least 95% sequence identity to or comprising SEQ ID NO: 2 or amino acids 20 to 882 of SEQ ID NO: 2; and (b) a polypeptide encoded by a polynucleotide comprising a nucleotide sequence having at least 95% sequence identity to or comprising SEQ ID NO: 1 or nucleotides 58 to 2774 of SEQ ID NO: 1, or the cDNA thereof; wherein the trypsin-like serine protease is selected from the group consisting of: (a) a polypeptide comprising an amino acid sequence having at least 95% sequence identity to or comprising SEQ ID NO: 6 or amino acids 20 to 259 of SEQ ID NO: 6; and (b) a polypeptide encoded by a polynucleotide comprising a nucleotide sequence having at least 95% sequence identity to or comprising SEQ ID NO: 5 or nucleotides 58 to 930 of SEQ ID NO: 5, or the cDNA thereof; wherein the second subtilisin-like serine protease is selected from the group consisting of: (a) a polypeptide comprising of an amino acid sequence having at least 95% sequence identity to or comprising SEQ ID NO: 100 or amino acids 16 to 540 of SEQ ID NO: 100; and (b) a polypeptide encoded by a polynucleotide comprising a nucleotide sequence having at least 95% sequence identity to or comprising SEQ ID NO: 99 or nucleotides 46 to 1681 of SEQ ID NO: 99, or the cDNA thereof; and wherein the second aspartic protease is selected from the group consisting of: (a) a polypeptide comprising an amino acid sequence having at least 95% sequence identity to or comprising SEQ ID NO: 108 or amino acids 18 to 395 of SEQ ID NO: 108; and (b) a polypeptide encoded by a polynucleotide comprising a nucleotide sequence having at least 95% sequence identity to or comprising SEQ ID NO: 107 or nucleotides 52 to 1339 of SEQ ID NO: 107, or the cDNA thereof.
 7. The isolated mutant of claim 6, wherein the first subtilisin-like serine protease comprises SEQ ID NO: 2 or amino acids 20 to 882 of SEQ ID NO:
 2. 8. The isolated mutant of claim 6, wherein the trypsin-like protease comprises SEQ ID NO: 6 or amino acids 20 to 259 of SEQ ID NO:
 6. 9. The isolated mutant of claim 6, wherein the second subtilisin-like serine protease comprises SEQ ID NO: 100 or amino acids 16 to 540 of SEQ ID NO:
 100. 10. The isolated mutant of claim 6, wherein the second aspartic protease comprises SEQ ID NO: 108 or amino acids 18 to 395 of SEQ ID NO:
 108. 